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 <p align="center" style="margin:0pt 0pt .0001pt;text-align:center;"><a name="scotch"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">As filed with the Securities and Exchange Commission on November 15, 2006</font></a></p> <div style="border:none;border-bottom:double windowtext 6.0pt;padding:0pt 0pt 0pt 0pt;"> <p align="right" style="border:none;margin:0pt 0pt 12.0pt;padding:0pt;text-align:right;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">REGISTRATION NO. 333 - &nbsp;&nbsp;&nbsp;&nbsp;</font></p> </div>

<p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p align="center" style="margin:0pt 0pt .0001pt;text-align:center;"><b><font size="5" face="Times New Roman" style="font-size:18.0pt;font-weight:bold;letter-spacing:-.1pt;">UNITED STATES</font></b></p>

<p align="center" style="margin:0pt 0pt .0001pt;text-align:center;"><b><font size="5" face="Times New Roman" style="font-size:18.0pt;font-weight:bold;letter-spacing:-.15pt;">SECURITIES AND EXCHANGE
COMMISSION</font></b></p>

<p align="center" style="margin:0pt 0pt 12.0pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;letter-spacing:-.15pt;">WASHINGTON,
D.C. 20549</font></b></p>

<p align="center" style="margin:0pt 0pt 12.0pt;text-align:center;"><b><font size="5" face="Times New Roman" style="font-size:18.0pt;font-weight:bold;letter-spacing:-.15pt;">FORM S-8</font></b></p>

<p align="center" style="margin:0pt 0pt 12.0pt;text-align:center;"><b><font size="3" face="Times New Roman" style="font-size:12.0pt;font-weight:bold;letter-spacing:-.15pt;">REGISTRATION
STATEMENT<br>
under the<br>
SECURITIES ACT OF 1933</font></b></p>

<p align="center" style="margin:0pt 0pt .0001pt;text-align:center;"><b><font size="5" face="Times New Roman" style="font-size:18.0pt;font-weight:bold;letter-spacing:-.15pt;">ImmunoGen, Inc.</font></b></p>

<p align="center" style="margin:0pt 0pt 12.0pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">(Exact
Name of Registrant as Specified in Its Charter)</font></p>

<div align="center">

<table border="0" cellspacing="0" cellpadding="0" width="100%" style="border-collapse:collapse;width:100.0%;">
 <tr>
  <td width="48%" valign="top" style="padding:0pt .7pt 0pt .7pt;width:48.8%;">
  <p align="center" style="font-size:10.0pt;margin:0pt 0pt .0001pt;text-align:center;"><!-- SET mrlNoTableShading --><b>Massachusetts</b></p>
  </td>
  <td width="2%" valign="bottom" style="padding:0pt .7pt 0pt .7pt;width:2.38%;">
  <p align="center" style="margin:0pt 0pt .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="48%" valign="top" style="padding:0pt .7pt 0pt .7pt;width:48.8%;">
  <p align="center" style="margin:0pt 0pt .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">04-2726691</font></b></p>
  </td>
 </tr>
 <tr>
  <td width="48%" valign="top" style="padding:0pt .7pt 0pt .7pt;width:48.8%;">
  <p align="center" style="margin:0pt 0pt .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(State or Other
  Jurisdiction</font></p>
  </td>
  <td width="2%" valign="bottom" style="padding:0pt .7pt 0pt .7pt;width:2.38%;">
  <p align="center" style="margin:0pt 0pt .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="48%" valign="top" style="padding:0pt .7pt 0pt .7pt;width:48.8%;">
  <p align="center" style="margin:0pt 0pt .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(I.R.S. Employer</font></p>
  </td>
 </tr>
 <tr>
  <td width="48%" valign="top" style="padding:0pt .7pt 0pt .7pt;width:48.8%;">
  <p align="center" style="margin:0pt 0pt .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">of Incorporation
  or Organization)</font></p>
  </td>
  <td width="2%" valign="bottom" style="padding:0pt .7pt 0pt .7pt;width:2.38%;">
  <p align="center" style="margin:0pt 0pt .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="48%" valign="top" style="padding:0pt .7pt 0pt .7pt;width:48.8%;">
  <p align="center" style="margin:0pt 0pt .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Identification
  No.)</font></p>
  </td>
 </tr>
</table>

</div>

<p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p align="center" style="margin:0pt 0pt .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">128 Sidney Street<br>
Cambridge, MA 02139</font></b></p>

<p align="center" style="margin:0pt 0pt 12.0pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">(Address,
Including Zip Code, of Principal Executive Offices)</font></p>

<p align="center" style="margin:0pt 0pt .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;letter-spacing:-.1pt;">IMMUNOGEN, INC.</font></b></p>

<p align="center" style="margin:0pt 0pt .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;letter-spacing:-.1pt;">2006 EMPLOYEE, DIRECTOR AND CONSULTANT
EQUITY INCENTIVE PLAN</font></b></p>

<p align="center" style="margin:0pt 0pt 12.0pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">(Full
Titles of the Plan)</font></p>

<p style="margin:0pt 0pt .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">MITCHEL SAYARE</font></b></p><p style="margin:0pt 0pt .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">CHAIRMAN OF THE BOARD &amp; CHIEF EXECUTIVE OFFICER</font></b></p><p style="margin:0pt 0pt .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">IMMUNOGEN, INC.</font></b></p><p style="margin:0pt 0pt .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">128 SIDNEY STREET</font></b></p><p style="margin:0pt 0pt .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">CAMBRIDGE, MA 02139</font></b></p><p style="margin:0pt 0pt .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">(617) 995-2500</font></b></p>

<p align="center" style="margin:0pt 0pt .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">(Name, Address and Telephone
Number, Including</font></p>

<p align="center" style="margin:0pt 0pt .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">Area Code, of Agent For Service)</font></p>

<p align="center" style="margin:0pt 0pt .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p align="center" style="margin:0pt 0pt 12.0pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;letter-spacing:-.1pt;">CALCULATION
OF REGISTRATION FEE</font></b></p>

<table border="0" cellspacing="0" cellpadding="0" width="100%" style="border-collapse:collapse;width:100.0%;">
 <tr style="page-break-inside:avoid;">
  <td width="35%" valign="bottom" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0pt .7pt 0pt 0pt;width:35.96%;">
  <p style="font-size:8.0pt;font-weight:bold;line-height:8.0pt;margin:0pt 0pt .0001pt;page-break-after:avoid;text-align:center;"><!-- SET mrlNoTableShading -->Title&nbsp;of<br>
  Securities&nbsp;to&nbsp;be&nbsp;Registered</p>
  </td>
  <td width="2%" valign="bottom" style="padding:0pt .7pt 0pt 0pt;width:2.38%;">
  <p style="font-weight:bold;line-height:8.0pt;margin:0pt 0pt .0001pt;page-break-after:avoid;text-align:center;"><b><font size="1" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></b></p>
  </td>
  <td width="13%" valign="bottom" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0pt .7pt 0pt 0pt;width:13.66%;">
  <p style="font-weight:bold;line-height:8.0pt;margin:0pt 0pt .0001pt;page-break-after:avoid;text-align:center;"><b><font size="1" face="Times New Roman" style="font-size:8.0pt;">Amount&nbsp;to&nbsp;be<br>
  Registered(1)</font></b></p>
  </td>
  <td width="2%" valign="bottom" style="padding:0pt .7pt 0pt 0pt;width:2.38%;">
  <p style="font-weight:bold;line-height:8.0pt;margin:0pt 0pt .0001pt;page-break-after:avoid;text-align:center;"><b><font size="1" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></b></p>
  </td>
  <td width="13%" colspan="2" valign="bottom" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0pt .7pt 0pt 0pt;width:13.52%;">
  <p style="font-weight:bold;line-height:8.0pt;margin:0pt 0pt .0001pt;page-break-after:avoid;text-align:center;"><b><font size="1" face="Times New Roman" style="font-size:8.0pt;">Proposed<br>
  Maximum<br>
  Offering&nbsp;Price<br>
  Per&nbsp;Share&nbsp;(2)</font></b></p>
  </td>
  <td width="2%" valign="bottom" style="padding:0pt .7pt 0pt 0pt;width:2.38%;">
  <p style="font-weight:bold;line-height:8.0pt;margin:0pt 0pt .0001pt;page-break-after:avoid;text-align:center;"><b><font size="1" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></b></p>
  </td>
  <td width="13%" colspan="2" valign="bottom" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0pt .7pt 0pt 0pt;width:13.52%;">
  <p style="font-weight:bold;line-height:8.0pt;margin:0pt 0pt .0001pt;page-break-after:avoid;text-align:center;"><b><font size="1" face="Times New Roman" style="font-size:8.0pt;">Proposed<br>
  Maximum<br>
  Aggregate<br>
  Offering&nbsp;Price&nbsp;(2)</font></b></p>
  </td>
  <td width="2%" valign="bottom" style="padding:0pt .7pt 0pt 0pt;width:2.38%;">
  <p style="font-weight:bold;line-height:8.0pt;margin:0pt 0pt .0001pt;page-break-after:avoid;text-align:center;"><b><font size="1" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></b></p>
  </td>
  <td width="13%" colspan="2" valign="bottom" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0pt .7pt 0pt 0pt;width:13.52%;">
  <p style="font-weight:bold;line-height:8.0pt;margin:0pt 0pt .0001pt;page-break-after:avoid;text-align:center;"><b><font size="1" face="Times New Roman" style="font-size:8.0pt;">Amount&nbsp;of<br>
  Registration&nbsp;Fee</font></b></p>
  </td>
  <td width="0%" valign="bottom" style="padding:0pt .7pt 0pt 0pt;width:.34%;">
  <p style="font-weight:bold;line-height:8.0pt;margin:0pt 0pt .0001pt;text-align:center;"><b><font size="1" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></b></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="35%" valign="top" style="border:none;padding:0pt .7pt 0pt 0pt;width:35.96%;">
  <p style="margin:0pt 0pt .0001pt 10.0pt;page-break-after:avoid;text-indent:-10.0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="2%" valign="bottom" style="padding:0pt .7pt 0pt 0pt;width:2.38%;">
  <p style="margin:0pt 0pt .0001pt;page-break-after:avoid;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="13%" valign="bottom" style="border:none;padding:0pt .7pt 0pt 0pt;width:13.66%;">
  <p style="margin:0pt 0pt .0001pt;page-break-after:avoid;text-align:right;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="2%" valign="bottom" style="padding:0pt .7pt 0pt 0pt;width:2.38%;">
  <p style="margin:0pt 0pt .0001pt;page-break-after:avoid;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="13%" colspan="2" valign="bottom" style="border:none;padding:0pt .7pt 0pt 0pt;width:13.52%;">
  <p style="margin:0pt 0pt .0001pt;page-break-after:avoid;text-align:right;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="2%" valign="bottom" style="padding:0pt .7pt 0pt 0pt;width:2.38%;">
  <p style="margin:0pt 0pt .0001pt;page-break-after:avoid;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="13%" colspan="2" valign="bottom" style="border:none;padding:0pt .7pt 0pt 0pt;width:13.52%;">
  <p style="margin:0pt 0pt .0001pt;page-break-after:avoid;text-align:right;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="2%" valign="bottom" style="padding:0pt .7pt 0pt 0pt;width:2.38%;">
  <p style="margin:0pt 0pt .0001pt;page-break-after:avoid;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="13%" colspan="2" valign="bottom" style="border:none;padding:0pt .7pt 0pt 0pt;width:13.52%;">
  <p style="margin:0pt 0pt .0001pt;page-break-after:avoid;text-align:right;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="0%" valign="bottom" style="padding:0pt .7pt 0pt 0pt;width:.34%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="35%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:35.96%;">
  <p style="margin:0pt 0pt .0001pt 10.0pt;text-indent:-10.0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Common Stock, $0.01 par value</font></p>
  </td>
  <td width="2%" valign="bottom" style="padding:0pt .7pt 0pt 0pt;width:2.38%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="13%" valign="bottom" style="padding:0pt .7pt 0pt 0pt;width:13.66%;">
  <p style="margin:0pt 0pt .0001pt;text-align:right;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">2,500,000 shares</font></p>
  </td>
  <td width="2%" valign="bottom" style="padding:0pt .7pt 0pt 0pt;width:2.38%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="1%" valign="bottom" style="padding:0pt 0pt 0pt 0pt;width:1.0%;">
  <p align="left" style="margin:0pt 0pt .0001pt;text-align:left;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">$</font></p>
  </td>
  <td width="12%" valign="bottom" style="padding:0pt .7pt 0pt 0pt;width:12.52%;">
  <p style="margin:0pt 0pt .0001pt;text-align:right;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">4.38</font></p>
  </td>
  <td width="2%" valign="bottom" style="padding:0pt .7pt 0pt 0pt;width:2.38%;">
  <p style="margin:0pt 0pt .0001pt;text-align:right;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="1%" valign="bottom" style="padding:0pt 0pt 0pt 0pt;width:1.0%;">
  <p align="left" style="margin:0pt 0pt .0001pt;text-align:left;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">$</font></p>
  </td>
  <td width="12%" valign="bottom" style="padding:0pt .7pt 0pt 0pt;width:12.52%;">
  <p style="margin:0pt 0pt .0001pt;text-align:right;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">10,937,500</font></p>
  </td>
  <td width="2%" valign="bottom" style="padding:0pt .7pt 0pt 0pt;width:2.38%;">
  <p style="margin:0pt 0pt .0001pt;text-align:right;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="1%" valign="bottom" style="padding:0pt 0pt 0pt 0pt;width:1.0%;">
  <p align="left" style="margin:0pt 0pt .0001pt;text-align:left;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">$</font></p>
  </td>
  <td width="12%" valign="bottom" style="padding:0pt .7pt 0pt 0pt;width:12.52%;">
  <p style="margin:0pt 0pt .0001pt;text-align:right;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">1,170.31</font></p>
  </td>
  <td width="0%" valign="bottom" style="padding:0pt .7pt 0pt 0pt;width:.34%;">
  <p style="margin:0pt 0pt .0001pt;text-align:right;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr height="0">
  <td width="269" style="border:none;"></td>
  <td width="18" style="border:none;"></td>
  <td width="102" style="border:none;"></td>
  <td width="18" style="border:none;"></td>
  <td width="7" style="border:none;"></td>
  <td width="94" style="border:none;"></td>
  <td width="18" style="border:none;"></td>
  <td width="7" style="border:none;"></td>
  <td width="94" style="border:none;"></td>
  <td width="18" style="border:none;"></td>
  <td width="7" style="border:none;"></td>
  <td width="94" style="border:none;"></td>
  <td width="2" style="border:none;"></td>
 </tr>
</table>

<p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<div style="margin:0pt 0pt .0001pt;page-break-after:avoid;"><hr size="1" width="160" noshade color="black" align="left" style="width:120.0pt;"></div>

<p style="font-size:10.0pt;margin:0pt 0pt 12.0pt 18.0pt;text-indent:-18.0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">(1)</font><font size="1" style="font-size:3.0pt;letter-spacing:-.1pt;">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; </font><font style="letter-spacing:-.1pt;">The number of shares of common stock, par value<b> </b>$.01 per share (&#147;Common Stock&#148;), stated above consists of
the aggregate number of shares which may be sold upon the exercise of options
or issuance of stock awards which may hereafter be granted under the ImmunoGen,
Inc. 2006 Employee, Director and Consultant Equity Incentive Plan (the &#147;Plan&#148;).&#160; The maximum number of shares which may be
sold upon the exercise of such options or issuance of stock awards granted
under the Plan is subject to adjustment in accordance with certain anti-dilution
and other provisions of the Plan.&#160;
Accordingly, pursuant to Rule&nbsp;416 under the Securities Act of 1933,
as amended (the &#147;Securities Act&#148;), this Registration Statement covers, in
addition to the number of shares stated above, an indeterminate number of
shares which may be subject to grant or otherwise issuable after the operation
of any such anti-dilution and other provisions.</font></p>

<p style="font-size:10.0pt;margin:0pt 0pt 12.0pt 18.0pt;text-indent:-18.0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">(2)</font><font size="1" style="font-size:3.0pt;letter-spacing:-.1pt;">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; </font>The
registration fee is computed, in accordance with Rule&nbsp;457(c) and Rule
457(h) under the Securities Act, based on the average of the high and low
prices of the registrant&#146;s common stock reported on the<font style="letter-spacing:-.1pt;"> NASDAQ Stock Market LLC</font> on November 10, 2006<font style="letter-spacing:-.1pt;">.</font></p>


 <div style="border:none;border-bottom:double windowtext 6.0pt;padding:0pt 0pt 0pt 0pt;"> <p style="border:none;margin:0pt 0pt .0001pt;padding:0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p> </div>
</div><br><hr size="3" width="100%" noshade color="#010101" align="center">

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<div>
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<p align="center" style="margin:0pt 0pt 12.0pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;letter-spacing:-.1pt;">PART II</font></b></p>

<p align="center" style="margin:0pt 0pt 12.0pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;letter-spacing:-.1pt;">INFORMATION
REQUIRED IN THE REGISTRATION STATEMENT</font></b></p>

<p style="font-family:Times New Roman;font-size:10.0pt;margin:0pt 0pt 12.0pt;"><u><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">Item 3.&#160; Incorporation of Certain Documents by
Reference</font></u><font style="letter-spacing:-.1pt;">.</font></p>

<p style="margin:0pt 0pt 12.0pt;text-indent:36.0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">The following documents
filed by the Registrant with the Commission are incorporated herein by
reference:</font></p>

<p style="font-family:Times New Roman;font-size:10.0pt;margin:0pt 0pt 12.0pt 36.0pt;text-indent:-18.0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">1.</font><font size="1" style="font-size:3.0pt;letter-spacing:-.1pt;">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; </font><font style="letter-spacing:-.1pt;">The Registrant&#146;s Annual Report on Form 10-K for
the fiscal year ended June 30, 2006, as filed on August 28, 2006 and amended on
September 11, 2006.</font></p>

<p style="font-family:Times New Roman;font-size:10.0pt;margin:0pt 0pt 12.0pt 36.0pt;text-indent:-18.0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">2.</font><font size="1" style="font-size:3.0pt;letter-spacing:-.1pt;">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; </font><font style="letter-spacing:-.1pt;">The Registrant&#146;s Quarterly Report on Form 10-Q for
the quarter ended September 30, 2006.</font></p>

<p style="font-family:Times New Roman;font-size:10.0pt;margin:0pt 0pt 12.0pt 36.0pt;text-indent:-18.0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">3.</font><font size="1" style="font-size:3.0pt;letter-spacing:-.1pt;">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; </font><font style="letter-spacing:-.1pt;">The Registrant&#146;s Current Report on Form 8-K, filed
with the Commission on July 12, 2006.</font></p>

<p style="font-family:Times New Roman;font-size:10.0pt;margin:0pt 0pt 12.0pt 36.0pt;text-indent:-18.0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">4.</font><font size="1" style="font-size:3.0pt;letter-spacing:-.1pt;">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; </font><font style="letter-spacing:-.1pt;">The Registrant&#146;s Current Report on Form 8-K, filed
with the Commission on September 5, 2006.</font></p>

<p style="font-family:Times New Roman;font-size:10.0pt;margin:0pt 0pt 12.0pt 36.0pt;text-indent:-18.0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">5.</font><font size="1" style="font-size:3.0pt;letter-spacing:-.1pt;">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; </font><font style="letter-spacing:-.1pt;">The Registrant&#146;s Current Report on Form 8-K, filed
with the Commission on September 11, 2006.</font></p>

<p style="font-family:Times New Roman;font-size:10.0pt;margin:0pt 0pt 12.0pt 36.0pt;text-indent:-18.0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">6.</font><font size="1" style="font-size:3.0pt;letter-spacing:-.1pt;">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; </font><font style="letter-spacing:-.1pt;">The Registrant&#146;s Current Report on Form 8-K, filed
with the Commission on October 4, 2006.</font></p>

<p style="font-family:Times New Roman;font-size:10.0pt;margin:0pt 0pt 12.0pt 36.0pt;text-indent:-18.0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">7.</font><font size="1" style="font-size:3.0pt;letter-spacing:-.1pt;">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; </font><font style="letter-spacing:-.1pt;">The Registrant&#146;s Current Report on Form 8-K, filed
with the Commission on October 19, 2006.</font></p>

<p style="font-family:Times New Roman;font-size:10.0pt;margin:0pt 0pt 12.0pt 36.0pt;text-indent:-18.0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">8.</font><font size="1" style="font-size:3.0pt;letter-spacing:-.1pt;">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; </font><font style="letter-spacing:-.1pt;">The Registrant&#146;s Current Report on Form 8-K, filed
with the Commission on November 8, 2006.</font></p>

<p style="font-family:Times New Roman;font-size:10.0pt;margin:0pt 0pt 12.0pt 36.0pt;text-indent:-18.0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">9.</font><font size="1" style="font-size:3.0pt;letter-spacing:-.1pt;">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; </font><font style="letter-spacing:-.1pt;">The Registrant&#146;s Current Report on Form 8-K, filed
with the Commission on November 13, 2006.</font></p>

<p style="font-family:Times New Roman;font-size:10.0pt;margin:0pt 0pt 12.0pt 36.0pt;text-indent:-18.0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">10.</font><font size="1" style="font-size:3.0pt;letter-spacing:-.1pt;">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; </font><font style="letter-spacing:-.1pt;">The description of the Company&#146;s common stock contained in the Company&#146;s
registration statement on Form 8-A under the Exchange Act (File No. 000-17999),
including amendments or reports filed for the purpose of updating such
description.</font></p>

<p style="margin:0pt 0pt 12.0pt;text-indent:36.0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">All
reports and other documents filed by the Registrant after the date hereof
pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act prior to
the filing of a post-effective amendment which indicates that all securities
offered hereby have been sold or which deregisters all securities then
remaining unsold, shall be deemed to be incorporated by reference herein and to
be part hereof from the date of filing of such reports and documents.</font></p>

<p style="font-family:Times New Roman;font-size:10.0pt;margin:0pt 0pt 12.0pt;"><u><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">Item 4.&#160; Description of Securities</font></u><font style="letter-spacing:-.1pt;">.</font></p>

<p style="margin:0pt 0pt 12.0pt;text-indent:36.0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">Not
applicable.</font></p>

<p style="font-family:Times New Roman;font-size:10.0pt;margin:0pt 0pt 12.0pt;"><u><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">Item 5.&#160; Interests of Named Experts and Counsel</font></u><font style="letter-spacing:-.1pt;">.</font></p>

<p style="margin:0pt 0pt 12.0pt;text-indent:36.0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">The validity of the issuance of the shares of common
stock registered under this Registration Statement has been passed upon for the
Registrant by Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C., Boston,
Massachusetts.</font></p>


 <p style="font-size:10.0pt;margin:24.0pt 0pt .0001pt;text-align:center;"><font face="Times New Roman">2</font></p> <br><hr size="3" width="100%" noshade color="#010101" align="center">

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 <p style="margin:0pt 0pt .0001pt;text-align:center;"></p>


<p style="font-family:Times New Roman;font-size:10.0pt;margin:0pt 0pt 12.0pt;"><u><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">Item 6.&#160; Indemnification of Directors and Officers</font></u><font style="letter-spacing:-.1pt;">.</font></p>

<p style="letter-spacing:-.1pt;margin:0pt 0pt 12.0pt;text-indent:36.0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Incorporated by
reference from the Registrant&#146;s Registration Statement on Form S-8, File No.
333-122553.</font></p>

<p style="font-family:Times New Roman;font-size:10.0pt;margin:0pt 0pt 12.0pt;"><u><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">Item 7.&#160; Exemption from Registration Claimed</font></u><font style="letter-spacing:-.1pt;">.</font></p>

<p style="margin:0pt 0pt 12.0pt;page-break-after:avoid;text-indent:36.0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">Not applicable.</font></p>

<p style="font-family:Times New Roman;font-size:10.0pt;margin:0pt 0pt 12.0pt;page-break-after:avoid;"><u><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">Item 8.&#160; Exhibits</font></u><font style="letter-spacing:-.1pt;">.</font></p>

<table border="0" cellspacing="0" cellpadding="0" style="border-collapse:collapse;font-family:Times New Roman;margin-left:40.0pt;">
 <tr style="page-break-inside:avoid;">
  <td width="50" valign="top" style="padding:0pt .7pt 0pt 0pt;width:37.4pt;">
  <p style="font-size:10.0pt;margin:0pt 0pt .0001pt;"><!-- SET mrlHTMLTableLeft --><!-- SET mrlNoTableShading -->(4.1)</p>
  </td>
  <td width="570" valign="top" style="padding:0pt .7pt 0pt 0pt;width:427.3pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Restated Articles of Organization (filed with the
  Commission as an exhibit to, and incorporated herein by reference from, the
  Registrant&#146;s Registration Statement on Form S-1, File No. 33-38883).</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="50" valign="top" style="padding:0pt .7pt 0pt 0pt;width:37.4pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="570" valign="top" style="padding:0pt .7pt 0pt 0pt;width:427.3pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="50" valign="top" style="padding:0pt .7pt 0pt 0pt;width:37.4pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(4.2)</font></p>
  </td>
  <td width="570" valign="top" style="padding:0pt .7pt 0pt 0pt;width:427.3pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Article 4 of the Restated Articles of Organization
  as amended (filed with the Commission as an exhibit to, and incorporated
  herein by reference from, the Registrant&#146;s Registration Statement on Form
  S-1, File No. 33-38883).</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="50" valign="top" style="padding:0pt .7pt 0pt 0pt;width:37.4pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="570" valign="top" style="padding:0pt .7pt 0pt 0pt;width:427.3pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="50" valign="top" style="padding:0pt .7pt 0pt 0pt;width:37.4pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(4.3)</font></p>
  </td>
  <td width="570" valign="top" style="padding:0pt .7pt 0pt 0pt;width:427.3pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Articles of Amendment to Restated Articles of
  Organization (filed as an exhibit to, and incorporated herein by reference
  from, the Registrant&#146;s quarterly report on Form 10-Q for the fiscal quarter
  ended March 31, 2001).</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="50" valign="top" style="padding:0pt .7pt 0pt 0pt;width:37.4pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="570" valign="top" style="padding:0pt .7pt 0pt 0pt;width:427.3pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="50" valign="top" style="padding:0pt .7pt 0pt 0pt;width:37.4pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(4.4)</font></p>
  </td>
  <td width="570" valign="top" style="padding:0pt .7pt 0pt 0pt;width:427.3pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">By-Laws, as amended (filed with the Commission as
  Exhibit 3.1, and incorporated herein by reference from, the Registrant&#146;s
  current report on Form 8-K, filed on November 4, 2005).</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="50" valign="top" style="padding:0pt .7pt 0pt 0pt;width:37.4pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="570" valign="top" style="padding:0pt .7pt 0pt 0pt;width:427.3pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="50" valign="top" style="padding:0pt .7pt 0pt 0pt;width:37.4pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(4.5)</font></p>
  </td>
  <td width="570" valign="top" style="padding:0pt .7pt 0pt 0pt;width:427.3pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Form of Common Stock Certificate (filed as an
  exhibit to, and incorporated herein by reference from, the Registrant&#146;s
  Registration Statement on Form S-1, File No. 333-31219).</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="50" valign="top" style="padding:0pt .7pt 0pt 0pt;width:37.4pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="570" valign="top" style="padding:0pt .7pt 0pt 0pt;width:427.3pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="50" valign="top" style="padding:0pt .7pt 0pt 0pt;width:37.4pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(5)</font></p>
  </td>
  <td width="570" valign="top" style="padding:0pt .7pt 0pt 0pt;width:427.3pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Opinion of Mintz, Levin, Cohn, Ferris, Glovsky and
  Popeo, P.C. as to the legality of shares being registered.</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="50" valign="top" style="padding:0pt .7pt 0pt 0pt;width:37.4pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="570" valign="top" style="padding:0pt .7pt 0pt 0pt;width:427.3pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="50" valign="top" style="padding:0pt .7pt 0pt 0pt;width:37.4pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(23.1)</font></p>
  </td>
  <td width="570" valign="top" style="padding:0pt .7pt 0pt 0pt;width:427.3pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Consent of Mintz, Levin, Cohn, Ferris, Glovsky and
  Popeo, P.C. (included in opinion of counsel filed as Exhibit 5).</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="50" valign="top" style="padding:0pt .7pt 0pt 0pt;width:37.4pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="570" valign="top" style="padding:0pt .7pt 0pt 0pt;width:427.3pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="50" valign="top" style="padding:0pt .7pt 0pt 0pt;width:37.4pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(23.2)</font></p>
  </td>
  <td width="570" valign="top" style="padding:0pt .7pt 0pt 0pt;width:427.3pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman"><font style="font-size:10.0pt;letter-spacing:-.1pt;">Consent of </font>Ernst &amp;
  Young LLP<font style="letter-spacing:-.1pt;">.</font></font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="50" valign="top" style="padding:0pt .7pt 0pt 0pt;width:37.4pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="570" valign="top" style="padding:0pt .7pt 0pt 0pt;width:427.3pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="50" valign="top" style="padding:0pt .7pt 0pt 0pt;width:37.4pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(24)</font></p>
  </td>
  <td width="570" valign="top" style="padding:0pt .7pt 0pt 0pt;width:427.3pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Power of Attorney to file future amendments (set
  forth on the signature page of this Registration Statement).</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="50" valign="top" style="padding:0pt .7pt 0pt 0pt;width:37.4pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="570" valign="top" style="padding:0pt .7pt 0pt 0pt;width:427.3pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="50" valign="top" style="padding:0pt .7pt 0pt 0pt;width:37.4pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(99.1)</font></p>
  </td>
  <td width="570" valign="top" style="padding:0pt .7pt 0pt 0pt;width:427.3pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">ImmunoGen, Inc. 2006 Employee, Director and
  Consultant Equity Incentive Plan.</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="50" valign="top" style="padding:0pt .7pt 0pt 0pt;width:37.4pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="570" valign="top" style="padding:0pt .7pt 0pt 0pt;width:427.3pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="50" valign="top" style="padding:0pt .7pt 0pt 0pt;width:37.4pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(99.2)</font></p>
  </td>
  <td width="570" valign="top" style="padding:0pt .7pt 0pt 0pt;width:427.3pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Form of Incentive Stock Option Agreement.</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="50" valign="top" style="padding:0pt .7pt 0pt 0pt;width:37.4pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="570" valign="top" style="padding:0pt .7pt 0pt 0pt;width:427.3pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="50" valign="top" style="padding:0pt .7pt 0pt 0pt;width:37.4pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(99.3)</font></p>
  </td>
  <td width="570" valign="top" style="padding:0pt .7pt 0pt 0pt;width:427.3pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Form of Non-Qualified Stock Option Agreement.</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="50" valign="top" style="padding:0pt .7pt 0pt 0pt;width:37.4pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="570" valign="top" style="padding:0pt .7pt 0pt 0pt;width:427.3pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="50" valign="top" style="padding:0pt .7pt 0pt 0pt;width:37.4pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(99.4)</font></p>
  </td>
  <td width="570" valign="top" style="padding:0pt .7pt 0pt 0pt;width:427.3pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Form of Incentive Stock Option Agreement for
  Executives.</font></p>
  </td>
 </tr>
</table>


 <p style="font-size:10.0pt;margin:24.0pt 0pt .0001pt;text-align:center;"><font face="Times New Roman">3</font></p> <br><hr size="3" width="100%" noshade color="#010101" align="center">

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<p style="margin:0pt 0pt .0001pt 72.0pt;text-indent:-36.0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<table border="0" cellspacing="0" cellpadding="0" style="border-collapse:collapse;font-family:Times New Roman;margin-left:40.0pt;">
 <tr style="page-break-inside:avoid;">
  <td width="50" valign="top" style="padding:0pt .7pt 0pt 0pt;width:37.4pt;">
  <p style="font-size:10.0pt;margin:0pt 0pt .0001pt;"><!-- SET mrlNoTableShading --><!-- SET mrlHTMLTableLeft -->(99.5)</p>
  </td>
  <td width="570" valign="top" style="padding:0pt .7pt 0pt 0pt;width:427.3pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Form of Non-Qualified Stock Option Agreement for
  Executives.</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="50" valign="top" style="padding:0pt .7pt 0pt 0pt;width:37.4pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="570" valign="top" style="padding:0pt .7pt 0pt 0pt;width:427.3pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="50" valign="top" style="padding:0pt .7pt 0pt 0pt;width:37.4pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(99.6)</font></p>
  </td>
  <td width="570" valign="top" style="padding:0pt .7pt 0pt 0pt;width:427.3pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Form of Non-Qualified Stock Option Agreement for
  Directors.</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="50" valign="top" style="padding:0pt .7pt 0pt 0pt;width:37.4pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="570" valign="top" style="padding:0pt .7pt 0pt 0pt;width:427.3pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="50" valign="top" style="padding:0pt .7pt 0pt 0pt;width:37.4pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(99.7)</font></p>
  </td>
  <td width="570" valign="top" style="padding:0pt .7pt 0pt 0pt;width:427.3pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Form of Restricted Stock Agreement for
  Non-Executives.</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="50" valign="top" style="padding:0pt .7pt 0pt 0pt;width:37.4pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="570" valign="top" style="padding:0pt .7pt 0pt 0pt;width:427.3pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="50" valign="top" style="padding:0pt .7pt 0pt 0pt;width:37.4pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(99.8)</font></p>
  </td>
  <td width="570" valign="top" style="padding:0pt .7pt 0pt 0pt;width:427.3pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Form of Restricted Stock Agreement for Directors.</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="50" valign="top" style="padding:0pt .7pt 0pt 0pt;width:37.4pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="570" valign="top" style="padding:0pt .7pt 0pt 0pt;width:427.3pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="50" valign="top" style="padding:0pt .7pt 0pt 0pt;width:37.4pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(99.9)</font></p>
  </td>
  <td width="570" valign="top" style="padding:0pt .7pt 0pt 0pt;width:427.3pt;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Form of Restricted Stock Agreement for Executives.</font></p>
  </td>
 </tr>
</table>

<p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p style="font-family:Times New Roman;font-size:10.0pt;margin:0pt 0pt 12.0pt;page-break-after:avoid;"><u><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">Item 9.&#160; Undertakings</font></u><font style="letter-spacing:-.1pt;">.</font></p>

<p style="font-family:Times New Roman;font-size:10.0pt;margin:0pt 0pt 12.0pt 36.0pt;page-break-after:avoid;text-indent:-36.0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">(a)</font><font size="1" style="font-size:3.0pt;letter-spacing:-.1pt;">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; </font><font style="letter-spacing:-.1pt;">The undersigned Registrant hereby undertakes:</font></p>

<p style="margin:0pt 0pt 12.0pt 36.0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">(1)&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; To file, during any period in which offers or sales are
being made, a post-effective amendment to this registration statement:</font></p>

<p style="margin:0pt 0pt 12.0pt 72.0pt;text-indent:36.0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">(i)&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; To include any prospectus required
by Section 10(a)(3) of the Securities Act of 1933;</font></p>

<p style="margin:0pt 0pt 12.0pt 72.0pt;text-indent:36.0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">(ii)&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; To reflect in the prospectus any facts
or events arising after the effective date of the registration statement (or
the most recent post-effective amendment thereof) which, individually or in the
aggregate, represent a fundamental change in the information set forth in the registration
statement.&#160; Notwithstanding the
foregoing, any increase or decrease in volume of securities offered (if the
total dollar value of securities offered would not exceed that which was
registered) and any deviation from the low or high end of the estimated maximum
offering range may be reflected in the form of prospectus filed with the
Commission pursuant to Rule 424(b) (&#167; 230.424(b) of this chapter) if, in the
aggregate, the changes in volume and price represent no more than a 20% change
in the maximum aggregate offering price set forth in the &#147;Calculation of
Registration Fee&#148; table in the effective registration statement.</font></p>

<p style="margin:0pt 0pt 12.0pt 72.0pt;text-indent:36.0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">(iii)&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; To include any material information
with respect to the plan of distribution not previously disclosed in the registration
statement or any material change to such information in the registration
statement;</font></p>

<p style="font-family:Times New Roman;font-size:10.0pt;margin:0pt 0pt 12.0pt 36.0pt;text-indent:36.0pt;"><i><font size="2" face="Times New Roman" style="font-size:10.0pt;font-style:italic;letter-spacing:-.1pt;">Provided, however</font></i><font style="letter-spacing:-.1pt;">, That:</font></p>

<p style="margin:0pt 0pt 12.0pt 36.0pt;text-indent:36.0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">(A) Paragraphs (a)(1)(i) and
(a)(1)(ii) of this section do not apply if the registration statement is on
Form S-8 (&#167; 230.16b of this chapter), and the information required to be
included in a post-effective amendment by those paragraphs is contained in
reports filed with or furnished to the Commission by the Registrant pursuant to
Section 13 or Section 15(d) of the Securities Exchange Act of 1934 (15 U.S.C.
78m or 78o(d)) that are incorporated by reference in this registration
statement; and</font></p>

<p style="margin:0pt 0pt 12.0pt 36.0pt;text-indent:36.0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">(B) Paragraphs (a)(1)(i),
(a)(1)(ii) and (a)(1)(iii) of this section do not apply if the registration
statement is on Form S-3 (&#167; 239.13 of this chapter) or Form F-3 (&#167; 239.33 of this
chapter) and the information required to be included in a post-effective
amendment by those paragraphs is contained in reports filed with or furnished
to the Commission by the Registrant pursuant to Section 13 or Section 15(d) of
the Securities Exchange Act of 1934 that are</font></p>


 <p style="font-size:10.0pt;margin:24.0pt 0pt .0001pt;text-align:center;"><font face="Times New Roman">4</font></p> <br><hr size="3" width="100%" noshade color="#010101" align="center">

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<p style="margin:0pt 0pt 12.0pt 36.0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">incorporated by reference in the registration statement, or is contained
in a form of prospectus filed pursuant to Rule 424(b) (&#167; 230.424(b) of this
chapter) that is part of the registration statement.</font></p>

<p style="margin:0pt 0pt 12.0pt 36.0pt;text-indent:36.0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">(C) <i>Provided
further, however</i>, that paragraphs (a)(1)(i) and (a)(1)(ii) do not
apply if the registration statement is for an offering of asset-backed
securities on Form S-1 (&#167; 239.11 of this chapter) or Form S-3 (&#167; 239.13 of this
chapter), and the information required to be included in a post-effective
amendment is provided pursuant to Item 1100(c) of Regulation AB (&#167;
229.1100(c)).</font></p>

<p style="margin:0pt 0pt 12.0pt 36.0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">(2)&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; That, for the purpose
of determining any liability under the Securities Act of 1933, each such
post-effective amendment shall be deemed to be a new registration statement
relating to the securities offered therein, and the offering of such securities
at that time shall be deemed to be the initial bona fide offering thereof.</font></p>

<p style="margin:0pt 0pt 12.0pt 36.0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">(3)&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; To remove from
registration by means of a post-effective amendment any of the securities being
registered which remain unsold at the termination of the offering.</font></p>

<p style="font-family:Times New Roman;font-size:10.0pt;margin:0pt 0pt 12.0pt 36.0pt;text-indent:-36.0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">(b)</font><font size="1" style="font-size:3.0pt;letter-spacing:-.1pt;">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; </font><font style="letter-spacing:-.1pt;">The undersigned Registrant hereby undertakes that,
for purposes of determining any liability under the Securities Act of 1933,
each filing of the Registrant&#146;s annual report pursuant to Section 13(a) or
Section 15(d) of the Securities Exchange Act of 1934 (and, where applicable,
each filing of an employee benefit plan&#146;s annual report pursuant to Section
15(d) of the Securities Exchange Act of 1934) that is incorporated by reference
in this registration statement shall be deemed to be a new registration
statement relating to the securities offered therein, and the offering of such
securities at that time shall be deemed to be the initial bona fide offering
thereof.</font></p>

<p style="font-family:Times New Roman;font-size:10.0pt;margin:0pt 0pt 12.0pt 36.0pt;text-indent:-36.0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">(c)</font><font size="1" style="font-size:3.0pt;letter-spacing:-.1pt;">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; </font><font style="letter-spacing:-.1pt;">Insofar as indemnification for liabilities arising
under the Securities Act of 1933 may be permitted to directors, officers and
controlling persons of the Registrant pursuant to the foregoing provisions, or
otherwise, the Registrant has been advised that in the opinion of the
Securities and Exchange Commission such indemnification is against public
policy as expressed in the Act and is, therefore, unenforceable.&#160; In the event that a claim for indemnification
against such liabilities (other than the payment by the Registrant of expenses
incurred or paid by a director, officer or controlling person of the Registrant
in the successful defense of any action, suit or proceeding) is asserted by
such director, officer or controlling person in connection with the securities
being registered, the Registrant will, unless in the opinion of its counsel the
matter has been settled by controlling precedent, submit to a court of
appropriate jurisdiction the question whether such indemnification by it is
against public policy as expressed in the Act and will be governed by the final
adjudication of such issue.</font></p>


 <p style="font-size:10.0pt;margin:24.0pt 0pt .0001pt;text-align:center;"><font face="Times New Roman">5</font></p> <br><hr size="3" width="100%" noshade color="#010101" align="center">

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<p align="center" style="margin:0pt 0pt 12.0pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;letter-spacing:-.1pt;">SIGNATURES</font></b></p>

<p style="font-family:Times New Roman;font-size:10.0pt;margin:0pt 0pt .0001pt;text-indent:36.0pt;"><i><font size="2" face="Times New Roman" style="font-size:10.0pt;font-style:italic;letter-spacing:-.1pt;">The Registrant</font></i><font style="letter-spacing:-.1pt;">.&#160; Pursuant
to the requirements of the Securities Act of 1933, the Registrant certifies
that it has reasonable grounds to believe that it meets all of the requirements
for filing on Form S-8 and has duly caused this Registration Statement to be
signed on its behalf by the undersigned, thereunto duly authorized, in Cambridge, Massachusetts on November
15, 2006.</font></p>

<p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<table border="0" cellspacing="0" cellpadding="0" width="100%" style="border-collapse:collapse;font-family:Times New Roman;width:100.0%;">
 <tr style="page-break-inside:avoid;">
  <td width="55%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:55.14%;">
  <p style="margin:0pt 0pt .0001pt;"><b><font size="2" face="Times New Roman" style="font-size:1.0pt;font-weight:bold;text-transform:uppercase;">&nbsp;</font></b></p>
  </td>
  <td width="44%" colspan="3" valign="top" style="padding:0pt .7pt 0pt 0pt;width:44.86%;">
  <p style="font-size:10.0pt;margin:0pt 0pt .0001pt;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;text-transform:uppercase;">immunogen, inc.</font></b><!-- SET mrlNoTableShading --></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="55%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:55.14%;">
  <p style="margin:0pt 0pt .0001pt;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;text-transform:uppercase;">&nbsp;</font></b></p>
  </td>
  <td width="44%" colspan="3" valign="top" style="padding:0pt .7pt 0pt 0pt;width:44.86%;">
  <p style="margin:0pt 0pt .0001pt;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;text-transform:uppercase;">&nbsp;</font></b></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="55%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:55.14%;">
  <p style="margin:0pt 0pt .0001pt;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">&nbsp;</font></b></p>
  </td>
  <td width="3%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:3.8%;">
  <p style="margin:0pt 0pt .0001pt;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">&nbsp;</font></b></p>
  </td>
  <td width="41%" colspan="2" valign="top" style="padding:0pt .7pt 0pt 0pt;width:41.06%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="55%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:55.14%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="3%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:3.8%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">By:</font></p>
  </td>
  <td width="16%" valign="top" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0pt .7pt 0pt 0pt;width:16.32%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">/s/ Mitchel Sayare</font></p>
  </td>
  <td width="24%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:24.74%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="55%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:55.14%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="3%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:3.8%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="41%" colspan="2" valign="top" style="padding:0pt .7pt 0pt 0pt;width:41.06%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Mitchel Sayare</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="55%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:55.14%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="3%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:3.8%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="41%" colspan="2" valign="top" style="padding:0pt .7pt 0pt 0pt;width:41.06%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Chairman of the
  Board of Directors</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="55%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:55.14%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="3%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:3.8%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="41%" colspan="2" valign="top" style="padding:0pt .7pt 0pt 0pt;width:41.06%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">President and
  Chief Executive Officer</font></p>
  </td>
 </tr>
</table>

<p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p style="margin:0pt 0pt 12.0pt;text-indent:36.0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">Each
person whose signature appears below constitutes and appoints Mitchel Sayare and
Daniel M. Junius, and each of them singly, his or her true and lawful attorneys-in-fact and agents, with full
power of substitution and resubstitution in each of them singly, for him or her
and in his or her name, place and stead, and in any and all capacities, to sign
any and all amendments (including post-effective amendments) to this
Registration Statement on Form&nbsp;S-8 of ImmunoGen, Inc., and to file the
same, with all exhibits thereto and other documents in connection therewith,
with the Securities and Exchange Commission, granting to the attorneys-in-fact
and agents, and each of them, full power and authority to do and perform each
and every act and thing requisite or necessary to be done in or about the
premises, as full to all intents and purposes as he or she might or could do in person, hereby ratifying and
confirming all that the attorneys-in-fact and agents or any of each of them or
their substitute may lawfully do or cause to be done by virtue hereof.</font></p>

<p style="margin:0pt 0pt 12.0pt;text-indent:36.0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">Pursuant
to the requirements of the Securities Act of 1933, this Registration Statement
has been signed by the following persons in the capacities and on the dates
indicated.</font></p>

<table border="0" cellspacing="0" cellpadding="0" width="100%" style="border-collapse:collapse;font-family:Times New Roman;width:100.0%;">
 <tr style="page-break-inside:avoid;">
  <td width="29%" colspan="5" valign="top" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0pt .7pt 0pt 0pt;width:29.84%;">
  <p style="font-size:10.0pt;margin:0pt 0pt .0001pt;"><!-- SET mrlNoTableShading --><b><font size="1" style="font-size:8.0pt;font-weight:bold;">Signature</font></b></p>
  </td>
  <td width="3%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:3.44%;">
  <p align="center" style="margin:0pt 0pt .0001pt;text-align:center;"><b><font size="1" face="Times New Roman" style="font-size:1.0pt;font-weight:bold;">&nbsp;</font></b></p>
  </td>
  <td width="36%" valign="top" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0pt .7pt 0pt 0pt;width:36.04%;">
  <p align="center" style="margin:0pt 0pt .0001pt;text-align:center;"><b><font size="1" face="Times New Roman" style="font-size:8.0pt;font-weight:bold;">Title</font></b></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.62%;">
  <p align="center" style="margin:0pt 0pt .0001pt;text-align:center;"><b><font size="1" face="Times New Roman" style="font-size:1.0pt;font-weight:bold;">&nbsp;</font></b></p>
  </td>
  <td width="28%" valign="top" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0pt .7pt 0pt 0pt;width:28.06%;">
  <p align="center" style="margin:0pt 0pt .0001pt;text-align:center;"><b><font size="1" face="Times New Roman" style="font-size:8.0pt;font-weight:bold;">Date</font></b></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="29%" colspan="5" valign="top" style="border:none;padding:0pt .7pt 0pt 0pt;width:29.84%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="3%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:3.44%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="36%" valign="top" style="border:none;padding:0pt .7pt 0pt 0pt;width:36.04%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.62%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="28%" valign="top" style="border:none;padding:0pt .7pt 0pt 0pt;width:28.06%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="17%" valign="top" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0pt .7pt 0pt 0pt;width:17.84%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">/s/ Mitchel
  Sayare</font></p>
  </td>
  <td width="12%" colspan="4" valign="top" style="padding:0pt .7pt 0pt 0pt;width:12.02%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="3%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:3.44%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="36%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:36.04%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Chairman of the Board of</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.62%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="28%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:28.06%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">November 15, 2006</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="29%" colspan="5" valign="top" style="padding:0pt .7pt 0pt 0pt;width:29.84%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Mitchel Sayare</font></p>
  </td>
  <td width="3%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:3.44%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="36%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:36.04%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Directors, President and</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.62%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="28%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:28.06%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="29%" colspan="5" valign="top" style="padding:0pt .7pt 0pt 0pt;width:29.84%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="3%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:3.44%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="36%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:36.04%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Chief Executive
  Officer</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.62%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="28%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:28.06%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="29%" colspan="5" valign="top" style="padding:0pt .7pt 0pt 0pt;width:29.84%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="3%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:3.44%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="36%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:36.04%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(Principal
  Executive Officer)</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.62%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="28%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:28.06%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="29%" colspan="5" valign="top" style="padding:0pt .7pt 0pt 0pt;width:29.84%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="3%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:3.44%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="36%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:36.04%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.62%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="28%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:28.06%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="19%" colspan="3" valign="top" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0pt .7pt 0pt 0pt;width:19.82%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;/s/ Daniel M. Junius</font></p>
  </td>
  <td width="10%" colspan="2" valign="top" style="padding:0pt .7pt 0pt 0pt;width:10.02%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="3%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:3.44%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="36%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:36.04%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Executive Vice President</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.62%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="28%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:28.06%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">November 15, 2006</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="29%" colspan="5" valign="top" style="padding:0pt .7pt 0pt 0pt;width:29.84%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Daniel M. Junius</font></p>
  </td>
  <td width="3%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:3.44%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="36%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:36.04%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">and Chief Financial Officer</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.62%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="28%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:28.06%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="29%" colspan="5" valign="top" style="padding:0pt .7pt 0pt 0pt;width:29.84%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="3%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:3.44%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="36%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:36.04%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(Principal
  Financial and</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.62%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="28%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:28.06%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="29%" colspan="5" valign="top" style="padding:0pt .7pt 0pt 0pt;width:29.84%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="3%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:3.44%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="36%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:36.04%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Accounting
  Officer)</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.62%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="28%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:28.06%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="29%" colspan="5" valign="top" style="padding:0pt .7pt 0pt 0pt;width:29.84%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="3%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:3.44%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="36%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:36.04%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.62%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="28%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:28.06%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="18%" colspan="2" valign="top" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0pt .7pt 0pt 0pt;width:18.82%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;/s/ David W. Carter</font></p>
  </td>
  <td width="11%" colspan="3" valign="top" style="padding:0pt .7pt 0pt 0pt;width:11.02%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="3%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:3.44%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="36%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:36.04%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Director</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.62%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="28%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:28.06%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">November 15, 2006</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="29%" colspan="5" valign="top" style="padding:0pt .7pt 0pt 0pt;width:29.84%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">David W. Carter</font></p>
  </td>
  <td width="3%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:3.44%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="36%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:36.04%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.62%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="28%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:28.06%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="29%" colspan="5" valign="top" style="padding:0pt .7pt 0pt 0pt;width:29.84%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="3%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:3.44%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="36%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:36.04%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.62%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="28%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:28.06%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="21%" colspan="4" valign="top" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0pt .7pt 0pt 0pt;width:21.8%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;/s/ Nicole Onetto, M.D.</font></p>
  </td>
  <td width="8%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:8.04%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="3%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:3.44%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="36%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:36.04%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Director</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.62%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="28%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:28.06%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">November 15, 2006</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="29%" colspan="5" valign="top" style="padding:0pt .7pt 0pt 0pt;width:29.84%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Nicole Onetto</font></p>
  </td>
  <td width="3%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:3.44%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="36%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:36.04%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.62%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="28%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:28.06%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr height="0">
  <td width="133" style="border:none;"></td>
  <td width="7" style="border:none;"></td>
  <td width="7" style="border:none;"></td>
  <td width="15" style="border:none;"></td>
  <td width="60" style="border:none;"></td>
  <td width="26" style="border:none;"></td>
  <td width="270" style="border:none;"></td>
  <td width="20" style="border:none;"></td>
  <td width="210" style="border:none;"></td>
 </tr>
</table>

<p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>


 <p style="font-size:10.0pt;margin:24.0pt 0pt .0001pt;text-align:center;"><font face="Times New Roman">6</font></p> <br><hr size="3" width="100%" noshade color="#010101" align="center">

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<p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<table border="0" cellspacing="0" cellpadding="0" width="100%" style="border-collapse:collapse;font-family:Times New Roman;width:100.0%;">
 <tr style="page-break-inside:avoid;">
  <td width="18%" valign="top" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0pt .7pt 0pt 0pt;width:18.78%;">
  <p style="font-size:10.0pt;margin:0pt 0pt .0001pt;"><!-- SET mrlNoTableShading -->&nbsp;/s/ Mark Skaletsky</p>
  </td>
  <td width="11%" colspan="2" valign="top" style="padding:0pt .7pt 0pt 0pt;width:11.06%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="3%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:3.44%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="36%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:36.04%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Director</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.62%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="28%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:28.06%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">November 15, 2006</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="29%" colspan="3" valign="top" style="padding:0pt .7pt 0pt 0pt;width:29.84%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Mark Skaletsky</font></p>
  </td>
  <td width="3%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:3.44%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="36%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:36.04%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.62%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="28%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:28.06%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="29%" colspan="3" valign="top" style="padding:0pt .7pt 0pt 0pt;width:29.84%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="3%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:3.44%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="36%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:36.04%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.62%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="28%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:28.06%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="20%" colspan="2" valign="top" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0pt .7pt 0pt 0pt;width:20.7%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">/s/ Joseph
  Villafranca</font></p>
  </td>
  <td width="9%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:9.16%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="3%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:3.44%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="36%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:36.04%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Director</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.62%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="28%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:28.06%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">November 15, 2006</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="29%" colspan="3" valign="top" style="padding:0pt .7pt 0pt 0pt;width:29.84%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Joseph
  Villafranca</font></p>
  </td>
  <td width="3%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:3.44%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="36%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:36.04%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.62%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="28%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:28.06%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr height="0">
  <td width="140" style="border:none;"></td>
  <td width="14" style="border:none;"></td>
  <td width="69" style="border:none;"></td>
  <td width="26" style="border:none;"></td>
  <td width="270" style="border:none;"></td>
  <td width="20" style="border:none;"></td>
  <td width="210" style="border:none;"></td>
 </tr>
</table>

<p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>


 <p style="font-size:10.0pt;margin:24.0pt 0pt .0001pt;text-align:center;"><font face="Times New Roman">7</font></p> <br><hr size="3" width="100%" noshade color="#010101" align="center">

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<p align="center" style="margin:0pt 0pt 12.0pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;letter-spacing:-.1pt;">ImmunoGen,
Inc.</font></b></p>

<p align="center" style="margin:0pt 0pt 12.0pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;letter-spacing:-.1pt;">INDEX TO
EXHIBITS FILED WITH<br>
FORM S-8 REGISTRATION STATEMENT</font></b></p>

<p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<table border="0" cellspacing="0" cellpadding="0" width="100%" style="border-collapse:collapse;font-family:Times New Roman;width:100.0%;">
 <tr style="page-break-inside:avoid;">
  <td width="11%" valign="bottom" style="padding:0pt .7pt 0pt 0pt;width:11.92%;">
  <p align="left" style="font-size:8.0pt;font-weight:bold;line-height:8.0pt;margin:0pt 0pt .0001pt;text-align:left;"><!-- SET mrlNoTableShading -->Exhibit</p>
  </td>
  <td width="2%" valign="bottom" style="padding:0pt .7pt 0pt 0pt;width:2.26%;">
  <p style="font-weight:bold;line-height:8.0pt;margin:0pt 0pt .0001pt;text-align:center;"><b><font size="1" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></b></p>
  </td>
  <td width="78%" valign="bottom" style="padding:0pt .7pt 0pt 0pt;width:78.86%;">
  <p style="font-weight:bold;line-height:8.0pt;margin:0pt 0pt .0001pt;text-align:center;"><b><font size="1" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></b></p>
  </td>
  <td width="6%" valign="bottom" style="padding:0pt .7pt 0pt 0pt;width:6.96%;">
  <p style="font-weight:bold;line-height:8.0pt;margin:0pt 0pt .0001pt;text-align:center;"><b><font size="1" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></b></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="11%" valign="bottom" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0pt .7pt 0pt 0pt;width:11.92%;">
  <p align="left" style="font-weight:bold;line-height:8.0pt;margin:0pt 0pt .0001pt;text-align:left;"><b><font size="1" face="Times New Roman" style="font-size:8.0pt;">Number</font></b></p>
  </td>
  <td width="2%" valign="bottom" style="padding:0pt .7pt 0pt 0pt;width:2.26%;">
  <p style="font-weight:bold;line-height:8.0pt;margin:0pt 0pt .0001pt;text-align:center;"><b><font size="1" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></b></p>
  </td>
  <td width="78%" valign="bottom" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0pt .7pt 0pt 0pt;width:78.86%;">
  <p style="font-weight:bold;line-height:8.0pt;margin:0pt 0pt .0001pt;text-align:center;"><b><font size="1" face="Times New Roman" style="font-size:8.0pt;">Description</font></b></p>
  </td>
  <td width="6%" valign="bottom" style="padding:0pt .7pt 0pt 0pt;width:6.96%;">
  <p style="font-weight:bold;line-height:8.0pt;margin:0pt 0pt .0001pt;text-align:center;"><b><font size="1" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></b></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="11%" valign="top" style="border:none;padding:0pt .7pt 0pt 0pt;width:11.92%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.26%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="78%" valign="top" style="border:none;padding:0pt .7pt 0pt 0pt;width:78.86%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="6%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:6.96%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="11%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:11.92%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(4.1)</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.26%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="78%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:78.86%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Restated Articles of Organization (filed with the
  Commission as an exhibit to, and incorporated herein by reference from, the
  Registrant&#146;s Registration Statement on Form S-1, File No. 33-38883).</font></p>
  </td>
  <td width="6%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:6.96%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="11%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:11.92%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(4.2)</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.26%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="78%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:78.86%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Article 4 of the Restated Articles of Organization
  as amended (filed with the Commission as an exhibit to, and incorporated
  herein by reference from, the Registrant&#146;s Registration Statement on Form
  S-1, File No. 33-38883).</font></p>
  </td>
  <td width="6%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:6.96%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="11%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:11.92%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(4.3)</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.26%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="78%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:78.86%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Articles of Amendment to Restated Articles of
  Organization (filed as an exhibit to, and incorporated herein by reference
  from, the Registrant&#146;s quarterly report on Form 10-Q for the fiscal quarter
  ended March 31, 2001).</font></p>
  </td>
  <td width="6%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:6.96%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="11%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:11.92%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(4.4)</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.26%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="78%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:78.86%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">By-Laws, as amended (filed with the Commission as
  Exhibit 3.1, and incorporated herein by reference from, the Registrant&#146;s
  current report on Form 8-K, filed on November 4, 2005).</font></p>
  </td>
  <td width="6%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:6.96%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="11%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:11.92%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(4.5)</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.26%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="78%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:78.86%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Form of Common Stock Certificate (filed with the
  Commission as an exhibit to, and incorporated herein by reference from, the
  Registrant&#146;s Registration Statement on Form S-1, File No. 333-31219).</font></p>
  </td>
  <td width="6%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:6.96%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="11%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:11.92%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(5)&nbsp;</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.26%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="78%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:78.86%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Opinion of Mintz, Levin, Cohn, Ferris, Glovsky and
  Popeo, P.C. as to the legality of shares being registered.</font></p>
  </td>
  <td width="6%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:6.96%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="11%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:11.92%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(23.1)</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.26%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="78%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:78.86%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Consent of Mintz, Levin, Cohn, Ferris, Glovsky and
  Popeo, P.C. (included in opinion of counsel filed as Exhibit 5).</font></p>
  </td>
  <td width="6%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:6.96%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="11%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:11.92%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(23.2)</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.26%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="78%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:78.86%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman"><font style="font-size:10.0pt;letter-spacing:-.1pt;">Consent of </font>Ernst &amp;
  Young LLP<font style="letter-spacing:-.1pt;">.</font></font></p>
  </td>
  <td width="6%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:6.96%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;letter-spacing:-.1pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="11%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:11.92%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(24)</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.26%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="78%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:78.86%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Power of Attorney to file future amendments (set
  forth on the signature page of this Registration Statement).</font></p>
  </td>
  <td width="6%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:6.96%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="11%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:11.92%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(99.1)</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.26%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="78%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:78.86%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">ImmunoGen, Inc. 2006 Employee, Director and
  Consultant Equity Incentive Plan.</font></p>
  </td>
  <td width="6%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:6.96%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="11%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:11.92%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(99.2)</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.26%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="78%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:78.86%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Form of Incentive Stock Option Agreement.</font></p>
  </td>
  <td width="6%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:6.96%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="11%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:11.92%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(99.3)</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.26%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="78%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:78.86%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Form of Non-Qualified Stock Option Agreement.</font></p>
  </td>
  <td width="6%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:6.96%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="11%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:11.92%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(99.4)</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.26%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="78%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:78.86%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Form of Incentive Stock Option Agreement for
  Executives.</font></p>
  </td>
  <td width="6%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:6.96%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="11%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:11.92%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(99.5)</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.26%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="78%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:78.86%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Form of Non-Qualified Stock Option Agreement for
  Executives</font></p>
  </td>
  <td width="6%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:6.96%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="11%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:11.92%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(99.6)</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.26%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="78%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:78.86%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Form of Non-Qualified Stock Option Agreement for
  Directors</font></p>
  </td>
  <td width="6%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:6.96%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="11%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:11.92%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(99.7)</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.26%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="78%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:78.86%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Form of Restricted Stock Agreement for
  Non-Executives.</font></p>
  </td>
  <td width="6%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:6.96%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="11%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:11.92%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(99.8)</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.26%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="78%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:78.86%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Form of Restricted Stock Agreement for Directors.</font></p>
  </td>
  <td width="6%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:6.96%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr style="page-break-inside:avoid;">
  <td width="11%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:11.92%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(99.9)</font></p>
  </td>
  <td width="2%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:2.26%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="78%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:78.86%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Form of Restricted Stock Agreement for Executives.</font></p>
  </td>
  <td width="6%" valign="top" style="padding:0pt .7pt 0pt 0pt;width:6.96%;">
  <p style="margin:0pt 0pt .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
 </tr>
</table>

<p style="margin:0pt 0pt 12.0pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>


 <p style="font-size:10.0pt;margin:24.0pt 0pt .0001pt;text-align:center;"><font face="Times New Roman">8</font></p>
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[{"type": "S-8", "sequence": "1", "filename": "a06-24023_1s8.htm", "description": "SECURITIES TO BE OFFERED TO EMPLOYEES PURSUANT TO EMPLOYEE BENEFIT PLANS", "secsgml_size_bytes": 116615}]
{"company-data": {"conformed-name": "IMMUNOGEN INC", "cik": "0000855654", "assigned-sic": "2834", "irs-number": "042726691", "state-of-incorporation": "MA", "fiscal-year-end": "0606"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-138713", "film-number": "061218364"}, "business-address": {"street1": "128 SIDNEY ST", "city": "CAMBRIDGE", "state": "MA", "zip": "02139", "phone": "6179952506"}, "mail-address": {"street1": "128 SIDNEY ST", "city": "CAMBRIDGE", "state": "MA", "zip": "02139"}}
As filed with the Securities and Exchange Commission on November 15, 2006
REGISTRATION NO. 333 -
UNITED STATES
SECURITIES AND EXCHANGE
COMMISSION
WASHINGTON,
D.C. 20549
FORM S-8
REGISTRATION
STATEMENT
under the
SECURITIES ACT OF 1933
ImmunoGen, Inc.
(Exact
Name of Registrant as Specified in Its Charter)
Massachusetts
04-2726691
(State or Other
  Jurisdiction
(I.R.S. Employer
of Incorporation
  or Organization)
Identification
  No.)
128 Sidney Street
Cambridge, MA 02139
(Address,
Including Zip Code, of Principal Executive Offices)
IMMUNOGEN, INC.
2006 EMPLOYEE, DIRECTOR AND CONSULTANT
EQUITY INCENTIVE PLAN
(Full
Titles of the Plan)
MITCHEL SAYARE
CHAIRMAN OF THE BOARD & CHIEF EXECUTIVE OFFICER
IMMUNOGEN, INC.
128 SIDNEY STREET
CAMBRIDGE, MA 02139
(617) 995-2500
(Name, Address and Telephone
Number, Including
Area Code, of Agent For Service)
CALCULATION
OF REGISTRATION FEE
Title of
Securities to be Registered
Amount to be
Registered(1)
Proposed
Maximum
Offering Price
Per Share (2)
Proposed
Maximum
Aggregate
Offering Price (2)
Amount of
Registration Fee
Common Stock, $0.01 par value
2,500,000 shares
$
4.38
$
10,937,500
$
1,170.31
(1)
The number of shares of common stock, par value
$.01 per share ("Common Stock"), stated above consists of
the aggregate number of shares which may be sold upon the exercise of options
or issuance of stock awards which may hereafter be granted under the ImmunoGen,
Inc. 2006 Employee, Director and Consultant Equity Incentive Plan (the "Plan").  The maximum number of shares which may be
sold upon the exercise of such options or issuance of stock awards granted
under the Plan is subject to adjustment in accordance with certain anti-dilution
and other provisions of the Plan. 
Accordingly, pursuant to Rule 416 under the Securities Act of 1933,
as amended (the "Securities Act"), this Registration Statement covers, in
addition to the number of shares stated above, an indeterminate number of
shares which may be subject to grant or otherwise issuable after the operation
of any such anti-dilution and other provisions.
(2)
The
registration fee is computed, in accordance with Rule 457(c) and Rule
457(h) under the Securities Act, based on the average of the high and low
prices of the registrant's common stock reported on the
NASDAQ Stock Market LLC
on November 10, 2006
.
PART II
INFORMATION
REQUIRED IN THE REGISTRATION STATEMENT
Item 3.  Incorporation of Certain Documents by
Reference
.
The following documents
filed by the Registrant with the Commission are incorporated herein by
reference:
1.
The Registrant's Annual Report on Form 10-K for
the fiscal year ended June 30, 2006, as filed on August 28, 2006 and amended on
September 11, 2006.
2.
The Registrant's Quarterly Report on Form 10-Q for
the quarter ended September 30, 2006.
3.
The Registrant's Current Report on Form 8-K, filed
with the Commission on July 12, 2006.
4.
The Registrant's Current Report on Form 8-K, filed
with the Commission on September 5, 2006.
5.
The Registrant's Current Report on Form 8-K, filed
with the Commission on September 11, 2006.
6.
The Registrant's Current Report on Form 8-K, filed
with the Commission on October 4, 2006.
7.
The Registrant's Current Report on Form 8-K, filed
with the Commission on October 19, 2006.
8.
The Registrant's Current Report on Form 8-K, filed
with the Commission on November 8, 2006.
9.
The Registrant's Current Report on Form 8-K, filed
with the Commission on November 13, 2006.
10.
The description of the Company's common stock contained in the Company's
registration statement on Form 8-A under the Exchange Act (File No. 000-17999),
including amendments or reports filed for the purpose of updating such
description.
All
reports and other documents filed by the Registrant after the date hereof
pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act prior to
the filing of a post-effective amendment which indicates that all securities
offered hereby have been sold or which deregisters all securities then
remaining unsold, shall be deemed to be incorporated by reference herein and to
be part hereof from the date of filing of such reports and documents.
Item 4.  Description of Securities
.
Not
applicable.
Item 5.  Interests of Named Experts and Counsel
.
The validity of the issuance of the shares of common
stock registered under this Registration Statement has been passed upon for the
Registrant by Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C., Boston,
Massachusetts.
2
Item 6.  Indemnification of Directors and Officers
.
Incorporated by
reference from the Registrant's Registration Statement on Form S-8, File No.
333-122553.
Item 7.  Exemption from Registration Claimed
.
Not applicable.
Item 8.  Exhibits
.
(4.1)
Restated Articles of Organization (filed with the
  Commission as an exhibit to, and incorporated herein by reference from, the
  Registrant's Registration Statement on Form S-1, File No. 33-38883).
(4.2)
Article 4 of the Restated Articles of Organization
  as amended (filed with the Commission as an exhibit to, and incorporated
  herein by reference from, the Registrant's Registration Statement on Form
  S-1, File No. 33-38883).
(4.3)
Articles of Amendment to Restated Articles of
  Organization (filed as an exhibit to, and incorporated herein by reference
  from, the Registrant's quarterly report on Form 10-Q for the fiscal quarter
  ended March 31, 2001).
(4.4)
By-Laws, as amended (filed with the Commission as
  Exhibit 3.1, and incorporated herein by reference from, the Registrant's
  current report on Form 8-K, filed on November 4, 2005).
(4.5)
Form of Common Stock Certificate (filed as an
  exhibit to, and incorporated herein by reference from, the Registrant's
  Registration Statement on Form S-1, File No. 333-31219).
(5)
Opinion of Mintz, Levin, Cohn, Ferris, Glovsky and
  Popeo, P.C. as to the legality of shares being registered.
(23.1)
Consent of Mintz, Levin, Cohn, Ferris, Glovsky and
  Popeo, P.C. (included in opinion of counsel filed as Exhibit 5).
(23.2)
Consent of
Ernst &
  Young LLP
.
(24)
Power of Attorney to file future amendments (set
  forth on the signature page of this Registration Statement).
(99.1)
ImmunoGen, Inc. 2006 Employee, Director and
  Consultant Equity Incentive Plan.
(99.2)
Form of Incentive Stock Option Agreement.
(99.3)
Form of Non-Qualified Stock Option Agreement.
(99.4)
Form of Incentive Stock Option Agreement for
  Executives.
3
(99.5)
Form of Non-Qualified Stock Option Agreement for
  Executives.
(99.6)
Form of Non-Qualified Stock Option Agreement for
  Directors.
(99.7)
Form of Restricted Stock Agreement for
  Non-Executives.
(99.8)
Form of Restricted Stock Agreement for Directors.
(99.9)
Form of Restricted Stock Agreement for Executives.
Item 9.  Undertakings
.
(a)
The undersigned Registrant hereby undertakes:
(1)           To file, during any period in which offers or sales are
being made, a post-effective amendment to this registration statement:
(i)            To include any prospectus required
by Section 10(a)(3) of the Securities Act of 1933;
(ii)           To reflect in the prospectus any facts
or events arising after the effective date of the registration statement (or
the most recent post-effective amendment thereof) which, individually or in the
aggregate, represent a fundamental change in the information set forth in the registration
statement.  Notwithstanding the
foregoing, any increase or decrease in volume of securities offered (if the
total dollar value of securities offered would not exceed that which was
registered) and any deviation from the low or high end of the estimated maximum
offering range may be reflected in the form of prospectus filed with the
Commission pursuant to Rule 424(b) (§ 230.424(b) of this chapter) if, in the
aggregate, the changes in volume and price represent no more than a 20% change
in the maximum aggregate offering price set forth in the "Calculation of
Registration Fee" table in the effective registration statement.
(iii)          To include any material information
with respect to the plan of distribution not previously disclosed in the registration
statement or any material change to such information in the registration
statement;
Provided, however
, That:
(A) Paragraphs (a)(1)(i) and
(a)(1)(ii) of this section do not apply if the registration statement is on
Form S-8 (§ 230.16b of this chapter), and the information required to be
included in a post-effective amendment by those paragraphs is contained in
reports filed with or furnished to the Commission by the Registrant pursuant to
Section 13 or Section 15(d) of the Securities Exchange Act of 1934 (15 U.S.C.
78m or 78o(d)) that are incorporated by reference in this registration
statement; and
(B) Paragraphs (a)(1)(i),
(a)(1)(ii) and (a)(1)(iii) of this section do not apply if the registration
statement is on Form S-3 (§ 239.13 of this chapter) or Form F-3 (§ 239.33 of this
chapter) and the information required to be included in a post-effective
amendment by those paragraphs is contained in reports filed with or furnished
to the Commission by the Registrant pursuant to Section 13 or Section 15(d) of
the Securities Exchange Act of 1934 that are
4
incorporated by reference in the registration statement, or is contained
in a form of prospectus filed pursuant to Rule 424(b) (§ 230.424(b) of this
chapter) that is part of the registration statement.
(C)
Provided
further, however
, that paragraphs (a)(1)(i) and (a)(1)(ii) do not
apply if the registration statement is for an offering of asset-backed
securities on Form S-1 (§ 239.11 of this chapter) or Form S-3 (§ 239.13 of this
chapter), and the information required to be included in a post-effective
amendment is provided pursuant to Item 1100(c) of Regulation AB (§
229.1100(c)).
(2)           That, for the purpose
of determining any liability under the Securities Act of 1933, each such
post-effective amendment shall be deemed to be a new registration statement
relating to the securities offered therein, and the offering of such securities
at that time shall be deemed to be the initial bona fide offering thereof.
(3)           To remove from
registration by means of a post-effective amendment any of the securities being
registered which remain unsold at the termination of the offering.
(b)
The undersigned Registrant hereby undertakes that,
for purposes of determining any liability under the Securities Act of 1933,
each filing of the Registrant's annual report pursuant to Section 13(a) or
Section 15(d) of the Securities Exchange Act of 1934 (and, where applicable,
each filing of an employee benefit plan's annual report pursuant to Section
15(d) of the Securities Exchange Act of 1934) that is incorporated by reference
in this registration statement shall be deemed to be a new registration
statement relating to the securities offered therein, and the offering of such
securities at that time shall be deemed to be the initial bona fide offering
thereof.
(c)
Insofar as indemnification for liabilities arising
under the Securities Act of 1933 may be permitted to directors, officers and
controlling persons of the Registrant pursuant to the foregoing provisions, or
otherwise, the Registrant has been advised that in the opinion of the
Securities and Exchange Commission such indemnification is against public
policy as expressed in the Act and is, therefore, unenforceable.  In the event that a claim for indemnification
against such liabilities (other than the payment by the Registrant of expenses
incurred or paid by a director, officer or controlling person of the Registrant
in the successful defense of any action, suit or proceeding) is asserted by
such director, officer or controlling person in connection with the securities
being registered, the Registrant will, unless in the opinion of its counsel the
matter has been settled by controlling precedent, submit to a court of
appropriate jurisdiction the question whether such indemnification by it is
against public policy as expressed in the Act and will be governed by the final
adjudication of such issue.
5
SIGNATURES
The Registrant
.  Pursuant
to the requirements of the Securities Act of 1933, the Registrant certifies
that it has reasonable grounds to believe that it meets all of the requirements
for filing on Form S-8 and has duly caused this Registration Statement to be
signed on its behalf by the undersigned, thereunto duly authorized, in Cambridge, Massachusetts on November
15, 2006.
immunogen, inc.
By:
/s/ Mitchel Sayare
Mitchel Sayare
Chairman of the
  Board of Directors
President and
  Chief Executive Officer
Each
person whose signature appears below constitutes and appoints Mitchel Sayare and
Daniel M. Junius, and each of them singly, his or her true and lawful attorneys-in-fact and agents, with full
power of substitution and resubstitution in each of them singly, for him or her
and in his or her name, place and stead, and in any and all capacities, to sign
any and all amendments (including post-effective amendments) to this
Registration Statement on Form S-8 of ImmunoGen, Inc., and to file the
same, with all exhibits thereto and other documents in connection therewith,
with the Securities and Exchange Commission, granting to the attorneys-in-fact
and agents, and each of them, full power and authority to do and perform each
and every act and thing requisite or necessary to be done in or about the
premises, as full to all intents and purposes as he or she might or could do in person, hereby ratifying and
confirming all that the attorneys-in-fact and agents or any of each of them or
their substitute may lawfully do or cause to be done by virtue hereof.
Pursuant
to the requirements of the Securities Act of 1933, this Registration Statement
has been signed by the following persons in the capacities and on the dates
indicated.
Signature
Title
Date
/s/ Mitchel
  Sayare
Chairman of the Board of
November 15, 2006
Mitchel Sayare
Directors, President and
Chief Executive
  Officer
(Principal
  Executive Officer)
/s/ Daniel M. Junius
Executive Vice President
November 15, 2006
Daniel M. Junius
and Chief Financial Officer
(Principal
  Financial and
Accounting
  Officer)
/s/ David W. Carter
Director
November 15, 2006
David W. Carter
/s/ Nicole Onetto, M.D.
Director
November 15, 2006
Nicole Onetto
6
/s/ Mark Skaletsky
Director
November 15, 2006
Mark Skaletsky
/s/ Joseph
  Villafranca
Director
November 15, 2006
Joseph
  Villafranca
7
ImmunoGen,
Inc.
INDEX TO
EXHIBITS FILED WITH
FORM S-8 REGISTRATION STATEMENT
Exhibit
Number
Description
(4.1)
Restated Articles of Organization (filed with the
  Commission as an exhibit to, and incorporated herein by reference from, the
  Registrant's Registration Statement on Form S-1, File No. 33-38883).
(4.2)
Article 4 of the Restated Articles of Organization
  as amended (filed with the Commission as an exhibit to, and incorporated
  herein by reference from, the Registrant's Registration Statement on Form
  S-1, File No. 33-38883).
(4.3)
Articles of Amendment to Restated Articles of
  Organization (filed as an exhibit to, and incorporated herein by reference
  from, the Registrant's quarterly report on Form 10-Q for the fiscal quarter
  ended March 31, 2001).
(4.4)
By-Laws, as amended (filed with the Commission as
  Exhibit 3.1, and incorporated herein by reference from, the Registrant's
  current report on Form 8-K, filed on November 4, 2005).
(4.5)
Form of Common Stock Certificate (filed with the
  Commission as an exhibit to, and incorporated herein by reference from, the
  Registrant's Registration Statement on Form S-1, File No. 333-31219).
(5)
Opinion of Mintz, Levin, Cohn, Ferris, Glovsky and
  Popeo, P.C. as to the legality of shares being registered.
(23.1)
Consent of Mintz, Levin, Cohn, Ferris, Glovsky and
  Popeo, P.C. (included in opinion of counsel filed as Exhibit 5).
(23.2)
Consent of
Ernst &
  Young LLP
.
(24)
Power of Attorney to file future amendments (set
  forth on the signature page of this Registration Statement).
(99.1)
ImmunoGen, Inc. 2006 Employee, Director and
  Consultant Equity Incentive Plan.
(99.2)
Form of Incentive Stock Option Agreement.
(99.3)
Form of Non-Qualified Stock Option Agreement.
(99.4)
Form of Incentive Stock Option Agreement for
  Executives.
(99.5)
Form of Non-Qualified Stock Option Agreement for
  Executives
(99.6)
Form of Non-Qualified Stock Option Agreement for
  Directors
(99.7)
Form of Restricted Stock Agreement for
  Non-Executives.
(99.8)
Form of Restricted Stock Agreement for Directors.
(99.9)
Form of Restricted Stock Agreement for Executives.
8