<PAGE>


     As filed with the Securities and Exchange Commission on July 3, 2001

                                            Registration No. 333-_______________



                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                    FORM S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

                            IGEN INTERNATIONAL, INC.
             (Exact name of registrant as specified in its charter)


             DELAWARE                                       94-2852543
  (State or other jurisdiction of                        (I.R.S. Employer
   incorporation or organization)                      Identification Number)

                             16020 INDUSTRIAL DRIVE
                          GAITHERSBURG, MARYLAND 20877
          (Address of Principal Executive Offices, including Zip Code)


                             1994 STOCK OPTION PLAN
                            (Full title of the plan)

                              SAMUEL J. WOHLSTADTER
                CHAIRMAN OF THE BOARD AND CHIEF EXECUTIVE OFFICER
                             16020 INDUSTRIAL DRIVE
                          GAITHERSBURG, MARYLAND 20877
                     (Name and address of agent for service)

                                 (301) 869-9800
          (Telephone number, including area code, of agent for service)
                                 ---------------
                                 WITH A COPY TO:

                             MEREDITH B. CROSS, ESQ.
                           WILMER, CUTLER & PICKERING
                               2445 M STREET, N.W.
                             WASHINGTON, D.C. 20037
                                 (202) 663-6000
                                -----------------

                         CALCULATION OF REGISTRATION FEE

<TABLE>
<CAPTION>
--------------------------------------------------------------------------------------------------------------------
                                                                   Proposed          Proposed
               Title of each                                       maximum           maximum
            class of securities                   Amount           offering         aggregate         Amount of
                   to be                          to be             price            offering        registration
                registered                      registered      per share (1)         price              fee
-------------------------------------------------------------------------------------------------------------------
<S>                                             <C>             <C>                 <C>               <C>
Common Stock, par value $0.001 per share
(including Series A Preferred Share
Purchase Rights)(2)                               750,000       $11.56-$23.03        $11,864,385      $2,966.10
-------------------------------------------------------------------------------------------------------------------
</TABLE>

<PAGE>

(1)      Estimated solely for the purpose of calculating the registration fee
         pursuant to Rule 457(h) under the Securities Act of 1933, as amended.
         The price per share and aggregate offering price are based upon (a) the
         actual exercise price for the additional shares subject to outstanding
         options granted under the 1994 Stock Option Plan and (b) the average of
         the high and low prices per share of IGEN Common Stock, par value $.001
         per share, as reported on The Nasdaq National Market on June 26, 2001,
         for additional shares reserved for future issuances pursuant to the
         1994 Stock Option Plan. The chart below details the calculation of the
         registration fee for the additional common stock issuable pursuant to
         outstanding options or reserved for issuance under the 1994 Stock
         Option Plan:

<TABLE>
<CAPTION>
         SECURITIES                     NUMBER OF SHARES         OFFERING PRICE PER SHARE  AGGREGATE OFFERING PRICE
         ----------                     ----------------         ------------------------  ------------------------
<S>                                     <C>                      <C>                        <C>
         Common stock issuable          400,000                  $18.75                     $7,500,000
         pursuant to outstanding
         options under the 1994 Stock
         Option Plan

         Common stock reserved for      322,242                  $11.56                     $3,725,118
         issuance under the 1994
         Stock Option Plan

         Common stock reserved for       27,758                  $23.03                     $639,267
         issuance under the 1994
         Stock Option Plan
                                                                 TOTAL:                     $11,864,385
</TABLE>


(2)      IGEN common stock includes associated rights to purchase shares of IGEN
         Series A Preferred Stock, par value $.001 per share. Until the
         occurrence of certain prescribed events, none of which has occurred,
         the Rights are not exercisable, are evidenced by the certificates
         representing IGEN common stock and will be transferred along with and
         only with the IGEN common stock. The value attributable to such Rights,
         if any, is reflected in the market price of IGEN common stock.

<PAGE>


                                EXPLANATORY NOTE

         IGEN International, Inc. ("Company") is filing this Registration
Statement on Form S-8 to register an additional 750,000 shares of the Company's
Common Stock, par value $.001 per share, issuable pursuant to the Company's 1994
Stock Option Plan ("Plan"). The Plan has been amended to reserve for issuance
these additional shares since the filing of the Company's original registration
statement covering the Plan. In accordance with General Instruction E to Form
S-8, the Company hereby incorporates herein by reference (1) the Form S-8
relating to the Plan that was previously filed with the Securities and Exchange
Commission on September 15, 1994 (SEC File No. 33-84042), together with all
exhibits filed therewith or incorporated therein by reference and (2) the
Post-Effective Amendment No. 1 to the Form S-8 that was previously filed with
the Securities and Exchange Commission on December 31, 1996 (File No. 33-84042),
together with all exhibits filed therewith or incorporated therein by reference.



<PAGE>


                                    PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 5.  INTERESTS OF NAMED EXPERTS AND COUNSEL.

         The validity of the additional common stock reserved for issuance under
the 1994 Stock Option Plan and registered hereby has been passed upon for the
Company by Wilmer, Cutler & Pickering, Washington, D.C. Richard Cass, a partner
of Wilmer, Cutler & Pickering, is a director of the Company and holds options to
purchase 10,000 shares of our common stock that were granted to Mr. Cass under
the Company's 1994 Non-employee Directors' Stock Option Plan.

ITEM 8.  EXHIBITS.

         In addition to those exhibits filed with the Registration Statement, as
amended, being incorporated by reference into this filing (SEC File No.
33-84042), each of the following exhibits is filed herewith or incorporated
by reference as indicated in the table below:

<TABLE>
<CAPTION>
       EXHIBIT
       NUMBER                    DESCRIPTION
       -------                   -----------
<S>              <C>
         5       Opinion of Wilmer, Cutler & Pickering as to the legality of the
                 securities being registered

        10.14    1994 Stock Option Plan, as amended on July 24, 1998 (1)

        23.1     Consent of Wilmer, Cutler & Pickering (included in Exhibit 5)

        23.2     Consent of Deloitte & Touche LLP

        24       Power of attorney (included on signature pages of this
                 registration statement)
</TABLE>

(1) Incorporated by reference to Exhibit 10.14 to the Company's Annual Report
    on Form 10-K for fiscal year ended March 31, 2001.

                                   SIGNATURES

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 the City of Gaithersburg, Montgomery County, State of Maryland on
this 27th day of June, 2001.

                                  IGEN International, Inc.

                                  By: /s/ SAMUEL J. WOHLSTADTER
                                      -------------------------------------
                                      Samuel J. Wohlstadter
                                      Chairman and Chief Executive Officer

<PAGE>



                                POWER OF ATTORNEY

KNOW ALL MEN BY THESE PRESENTS, that each person whose signature appears below
under the heading "Signature" constitutes and appoints Samuel J. Wohlstadter,
Richard J. Massey and George V. Migausky as his true and lawful
attorneys-in-fact each acting alone, with full power of substitution and
resubstitution, for him and in his name, place and stead in any and all
capacities to sign any or all amendments (including post-effective amendments)
to this registration statement and to file the same, with all exhibits thereto,
and other documents in connection therewith, with the Securities and Exchange
Commission, granting unto said attorneys-in-fact full power and authority to do
and perform each and every act and thing requisite and necessary to be done in
and about the premises, as fully for all intents and purposes as he might or
could do in person, hereby ratifying and confirming all that said
attorneys-in-fact, or their substitutes, each acting alone, 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.

<TABLE>
<CAPTION>
                       SIGNATURE                               CAPACITY                             DATE
                       ---------                               --------                             ----
<S>                                             <C>                                           <C>

        /s/ SAMUEL J. WOHLSTADTER               Chairman, Chief Executive Officer             June 27, 2001
        ---------------------------------       (Principal Executive Officer); Director
        Samuel J. Wohlstadter

        /s/ GEORGE V. MIGAUSKY                  Vice President and Chief Financial            June 27, 2001
        ---------------------------------       Officer (Principal Financial and
        George V. Migausky                      Accounting Officer)

        /s/ RICHARD J. MASSEY
        ---------------------------------       President;  Director                          June 27, 2001
        Richard J. Massey

        /s/ RICHARD W. CASS
        ---------------------------------       Director                                      June 27, 2001
        Richard W. Cass

        /s/ ANTHONY REES
        ---------------------------------       Director                                      June 29, 2001
        Anthony Rees

        /s/ ROBERT R. SALSMANS
        ---------------------------------       Director                                      June 27, 2001
        Robert R. Salsmans

</TABLE>



<PAGE>




                                  EXHIBIT INDEX

<TABLE>
<CAPTION>
        EXHIBIT
        NUMBER                        DESCRIPTION
        -------                       -----------
<S>                 <C>
          5         Opinion of Wilmer, Cutler & Pickering as to the legality of the
                    securities being registered

         10.14      1994 Stock Option Plan, as amended on July 24, 1998

         23.1       Consent of Wilmer, Cutler & Pickering (included in Exhibit 5)

         23.2       Consent of Deloitte & Touche LLP

         24         Power of attorney (included on signature pages of this registration
                    statement)

</TABLE>
[{"type": "S-8", "sequence": "1", "filename": "a2046102zs-8.txt", "description": "S-8", "secsgml_size_bytes": 12547}]
{"company-data": {"conformed-name": "IGEN INTERNATIONAL INC /DE", "cik": "0000916304", "assigned-sic": "6794", "irs-number": "942852543", "state-of-incorporation": "DE", "fiscal-year-end": "0331"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-64478", "film-number": "1674519"}, "business-address": {"street1": "16020 INDUSTRIAL DR", "city": "GAITHERSBURG", "state": "MD", "zip": "20877", "phone": "3019848000"}, "mail-address": {"street1": "16020 INDUSTRIAL DRIVE", "city": "GAITHERSBURG", "state": "MD", "zip": "20877"}, "former-company": {"former-conformed-name": "IGEN INC /CA/", "date-changed": "19931216"}}
As filed with the Securities and Exchange Commission on July 3, 2001

                                            Registration No. 333-_______________

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                    FORM S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

                            IGEN INTERNATIONAL, INC.
             (Exact name of registrant as specified in its charter)

             DELAWARE                                       94-2852543
  (State or other jurisdiction of                        (I.R.S. Employer
   incorporation or organization)                      Identification Number)

                             16020 INDUSTRIAL DRIVE
                          GAITHERSBURG, MARYLAND 20877
          (Address of Principal Executive Offices, including Zip Code)

                             1994 STOCK OPTION PLAN
                            (Full title of the plan)

                              SAMUEL J. WOHLSTADTER
                CHAIRMAN OF THE BOARD AND CHIEF EXECUTIVE OFFICER
                             16020 INDUSTRIAL DRIVE
                          GAITHERSBURG, MARYLAND 20877
                     (Name and address of agent for service)

                                 (301) 869-9800
          (Telephone number, including area code, of agent for service)
                                 ---------------
                                 WITH A COPY TO:

                             MEREDITH B. CROSS, ESQ.
                           WILMER, CUTLER & PICKERING
                               2445 M STREET, N.W.
                             WASHINGTON, D.C. 20037
                                 (202) 663-6000
                                -----------------

                         CALCULATION OF REGISTRATION FEE
--------------------------------------------------------------------------------------------------------------------
                                                                   Proposed          Proposed
               Title of each                                       maximum           maximum
            class of securities                   Amount           offering         aggregate         Amount of
                   to be                          to be             price            offering        registration
                registered                      registered      per share (1)         price              fee
-------------------------------------------------------------------------------------------------------------------
Common Stock, par value $0.001 per share
(including Series A Preferred Share
Purchase Rights)(2)                               750,000       $11.56-$23.03        $11,864,385      $2,966.10
-------------------------------------------------------------------------------------------------------------------
(1)      Estimated solely for the purpose of calculating the registration fee
         pursuant to Rule 457(h) under the Securities Act of 1933, as amended.
         The price per share and aggregate offering price are based upon (a) the
         actual exercise price for the additional shares subject to outstanding
         options granted under the 1994 Stock Option Plan and (b) the average of
         the high and low prices per share of IGEN Common Stock, par value $.001
         per share, as reported on The Nasdaq National Market on June 26, 2001,
         for additional shares reserved for future issuances pursuant to the
         1994 Stock Option Plan. The chart below details the calculation of the
         registration fee for the additional common stock issuable pursuant to
         outstanding options or reserved for issuance under the 1994 Stock
         Option Plan:
SECURITIES                     NUMBER OF SHARES         OFFERING PRICE PER SHARE  AGGREGATE OFFERING PRICE
         ----------                     ----------------         ------------------------  ------------------------
Common stock issuable          400,000                  $18.75                     $7,500,000
         pursuant to outstanding
         options under the 1994 Stock
         Option Plan

         Common stock reserved for      322,242                  $11.56                     $3,725,118
         issuance under the 1994
         Stock Option Plan

         Common stock reserved for       27,758                  $23.03                     $639,267
         issuance under the 1994
         Stock Option Plan
                                                                 TOTAL:                     $11,864,385
(2)      IGEN common stock includes associated rights to purchase shares of IGEN
         Series A Preferred Stock, par value $.001 per share. Until the
         occurrence of certain prescribed events, none of which has occurred,
         the Rights are not exercisable, are evidenced by the certificates
         representing IGEN common stock and will be transferred along with and
         only with the IGEN common stock. The value attributable to such Rights,
         if any, is reflected in the market price of IGEN common stock.
EXPLANATORY NOTE

         IGEN International, Inc. ("Company") is filing this Registration
Statement on Form S-8 to register an additional 750,000 shares of the Company's
Common Stock, par value $.001 per share, issuable pursuant to the Company's 1994
Stock Option Plan ("Plan"). The Plan has been amended to reserve for issuance
these additional shares since the filing of the Company's original registration
statement covering the Plan. In accordance with General Instruction E to Form
S-8, the Company hereby incorporates herein by reference (1) the Form S-8
relating to the Plan that was previously filed with the Securities and Exchange
Commission on September 15, 1994 (SEC File No. 33-84042), together with all
exhibits filed therewith or incorporated therein by reference and (2) the
Post-Effective Amendment No. 1 to the Form S-8 that was previously filed with
the Securities and Exchange Commission on December 31, 1996 (File No. 33-84042),
together with all exhibits filed therewith or incorporated therein by reference.
PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 5.  INTERESTS OF NAMED EXPERTS AND COUNSEL.

         The validity of the additional common stock reserved for issuance under
the 1994 Stock Option Plan and registered hereby has been passed upon for the
Company by Wilmer, Cutler & Pickering, Washington, D.C. Richard Cass, a partner
of Wilmer, Cutler & Pickering, is a director of the Company and holds options to
purchase 10,000 shares of our common stock that were granted to Mr. Cass under
the Company's 1994 Non-employee Directors' Stock Option Plan.

ITEM 8.  EXHIBITS.

         In addition to those exhibits filed with the Registration Statement, as
amended, being incorporated by reference into this filing (SEC File No.
33-84042), each of the following exhibits is filed herewith or incorporated
by reference as indicated in the table below:
EXHIBIT
       NUMBER                    DESCRIPTION
       -------                   -----------
5       Opinion of Wilmer, Cutler & Pickering as to the legality of the
                 securities being registered

        10.14    1994 Stock Option Plan, as amended on July 24, 1998 (1)

        23.1     Consent of Wilmer, Cutler & Pickering (included in Exhibit 5)

        23.2     Consent of Deloitte & Touche LLP

        24       Power of attorney (included on signature pages of this
                 registration statement)
(1) Incorporated by reference to Exhibit 10.14 to the Company's Annual Report
    on Form 10-K for fiscal year ended March 31, 2001.

                                   SIGNATURES

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 the City of Gaithersburg, Montgomery County, State of Maryland on
this 27th day of June, 2001.

                                  IGEN International, Inc.

                                  By: /s/ SAMUEL J. WOHLSTADTER
                                      -------------------------------------
                                      Samuel J. Wohlstadter
                                      Chairman and Chief Executive Officer
POWER OF ATTORNEY

KNOW ALL MEN BY THESE PRESENTS, that each person whose signature appears below
under the heading "Signature" constitutes and appoints Samuel J. Wohlstadter,
Richard J. Massey and George V. Migausky as his true and lawful
attorneys-in-fact each acting alone, with full power of substitution and
resubstitution, for him and in his name, place and stead in any and all
capacities to sign any or all amendments (including post-effective amendments)
to this registration statement and to file the same, with all exhibits thereto,
and other documents in connection therewith, with the Securities and Exchange
Commission, granting unto said attorneys-in-fact full power and authority to do
and perform each and every act and thing requisite and necessary to be done in
and about the premises, as fully for all intents and purposes as he might or
could do in person, hereby ratifying and confirming all that said
attorneys-in-fact, or their substitutes, each acting alone, 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                               CAPACITY                             DATE
                       ---------                               --------                             ----
/s/ SAMUEL J. WOHLSTADTER               Chairman, Chief Executive Officer             June 27, 2001
        ---------------------------------       (Principal Executive Officer); Director
        Samuel J. Wohlstadter

        /s/ GEORGE V. MIGAUSKY                  Vice President and Chief Financial            June 27, 2001
        ---------------------------------       Officer (Principal Financial and
        George V. Migausky                      Accounting Officer)

        /s/ RICHARD J. MASSEY
        ---------------------------------       President;  Director                          June 27, 2001
        Richard J. Massey

        /s/ RICHARD W. CASS
        ---------------------------------       Director                                      June 27, 2001
        Richard W. Cass

        /s/ ANTHONY REES
        ---------------------------------       Director                                      June 29, 2001
        Anthony Rees

        /s/ ROBERT R. SALSMANS
        ---------------------------------       Director                                      June 27, 2001
        Robert R. Salsmans
EXHIBIT INDEX
EXHIBIT
        NUMBER                        DESCRIPTION
        -------                       -----------
5         Opinion of Wilmer, Cutler & Pickering as to the legality of the
                    securities being registered

         10.14      1994 Stock Option Plan, as amended on July 24, 1998

         23.1       Consent of Wilmer, Cutler & Pickering (included in Exhibit 5)

         23.2       Consent of Deloitte & Touche LLP

         24         Power of attorney (included on signature pages of this registration
                    statement)