<PAGE>


      As filed with the Securities and Exchange Commission on July 10, 2001

                                                      Registration No. 333-_____
================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                      ------------------------------------

                                    FORM S-8

                          REGISTRATION STATEMENT UNDER
                           THE SECURITIES ACT OF 1933

                           BIOTRANSPLANT INCORPORATED
             (Exact Name of Registrant as Specified in Its Charter)

              DELAWARE                                      04-3119555
     (State or Other Jurisdiction of                     (I.R.S. Employer
     Incorporation or Organization)                      Identification No.)

   CHARLESTOWN NAVY YARD
 BUILDING 75, THIRD AVENUE
CHARLESTOWN, MASSACHUSETTS                                     02129
(Address of Principal Executive Offices)                     (Zip Code)

               ELIGIX, INC. 1997 EQUITY INCENTIVE PLAN, AS AMENDED
                                       AND
       ELIGIX, INC. AMENDED AND RESTATED MANAGEMENT EQUITY INCENTIVE PLAN
                            (Full Title of the Plans)

                              ELLIOT LEBOWITZ, Ph.D.
                      PRESIDENT AND CHIEF EXECUTIVE OFFICER
                           BIOTRANSPLANT INCORPORATED
                              CHARLESTOWN NAVY YARD
                            BUILDING 75, THIRD AVENUE
                        CHARLESTOWN, MASSACHUSETTS 02129
                     (Name and Address of Agent For Service)

                                 (617) 241-5200
          (Telephone Number, Including Area Code, of Agent For Service)

                         CALCULATION OF REGISTRATION FEE
<TABLE>
<CAPTION>
=====================================================================================================
                                           Proposed               Proposed
Title of                                   Maximum                Maximum
Securities to be     Amount to be          Offering Price Per     Aggregate          Amount of
Registered            Registered           Share                  Offering Price     Registration Fee
-----------------------------------------------------------------------------------------------------
<S>                  <C>                   <C>                    <C>                <C>
Common
Stock, $0.01
par value
per share            1,595,714 shares(1)   $7.01(2)               $11,185,955(2)        $2,797
=====================================================================================================
</TABLE>

(1)  Consists of (i) 605,714 shares issuable under the Eligix, Inc. 1997 Equity
     Incentive Plan, as amended and (ii) 990,000 shares issuable under the
     Eligix, Inc. Amended and Restated Management Equity Incentive Plan.

(2)  Estimated solely for the purpose of calculating the registration fee
     pursuant to Rules 457(c) and 457(h) of the Securities Act of 1933, as
     amended, and based upon the average of the high and low prices of the
     Registrant's Common Stock as reported on the Nasdaq National Market on
     July 6, 2001.




<PAGE>

                                     PART I
              INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS

     ITEM 1. PLAN INFORMATION.

     The information required by Item 1 is included in documents sent or given
to participants in the plans covered by this registration statement pursuant to
Rule 428(b)(1) of the Securities Act of 1933, as amended (the "Securities Act").

     ITEM 2. REGISTRANT INFORMATION AND EMPLOYEE PLAN ANNUAL INFORMATION.

     The written statement required by Item 2 is included in documents sent or
given to participants in the plans covered by this registration statement
pursuant to Rule 428(b)(1) of the Securities Act.

                                     PART II
               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

     ITEM 3. INCORPORATION OF DOCUMENTS BY REFERENCE.

     The registrant is subject to the informational and reporting requirements
of Sections 13(a), 14, and 15(d) of the Securities Exchange Act of 1934, as
amended (the "Exchange Act"), and in accordance therewith files reports, proxy
statements and other information with the Securities and Exchange Commission
(the "Commission"). The following documents, which are on file with the
Commission, are incorporated in this registration statement by reference:

     (a) The registrant's latest annual report filed pursuant to Section 13(a)
or 15(d) of the Exchange Act or the latest prospectus filed pursuant to Rule
424(b) under the Securities Act that contains audited financial statements for
the registrant's latest fiscal year for which such statements have been filed.

     (b) All other reports filed pursuant to Section 13(a) or 15(d) of the
Exchange Act since the end of the fiscal year covered by the document referred
to in (a) above.

     (c) The description of the securities contained in the registrant's
registration statement on Form 8-A filed under the Exchange Act, including any
amendment or report filed for the purpose of updating such description.

     All documents subsequently filed by the registrant 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 in this registration statement and to be
part hereof from the date of the filing of such documents. Any statement
contained in a document incorporated or deemed to be incorporated by reference
herein shall be deemed to be modified or superseded for the purposes of this
registration statement to the extent that a statement contained herein or in any
other subsequently filed document which also is or is deemed to be incorporated
by reference herein modifies or supersedes such statement. Any statement so
modified or superseded shall not be deemed, except as so modified or superseded,
to constitute a part of this registration statement.



                                      -1-
<PAGE>



     ITEM 4. DESCRIPTION OF SECURITIES.

     Not applicable.

     ITEM 5. INTERESTS OF NAMED EXPERTS AND COUNSEL.

     Hale and Dorr LLP has opined as to the legality of the securities being
offered by this registration statement. Steven D. Singer, a partner of Hale and
Dorr LLP, serves as Secretary to the registrant.

     ITEM 6. INDEMNIFICATION OF DIRECTORS AND OFFICERS.

     Article IX of the Company's Restated Certificate of Incorporation provides
that no director of the Company shall be personally liable for any monetary
damages for any breach of fiduciary duty as a director, except to the extent
that the Delaware General Corporation Law prohibits the elimination or
limitation of liability of directors for breach of fiduciary duty.

     Article X of the Company's Restated Certificate of Incorporation provides
that a director or officer of the Company (a) shall be indemnified by the
Company against all expenses (including attorneys' fees), judgments, fines, and
amounts paid in settlement incurred in connection with any litigation or other
legal proceeding (other than an action by or in the right of the Company)
brought against him by virtue of his position as a director or officer of the
Company if he acted in good faith and in a manner he reasonably believed to be
in, or not opposed to, the best interests of the Company, and, with respect to
any criminal action or proceeding, had no reasonable cause to believe his
conduct was unlawful and (b) shall be indemnified by the Company against all
expenses (including attorneys' fees) and amounts paid in settlement incurred in
connection with any action by or in the right of the Company brought against him
by virtue of his position as a director or officer of the Company if he acted in
good faith and in a manner he reasonably believed to be in, or not opposed to,
the best interests of the Company, except that no indemnification shall be made
with respect to any matter as to which such person shall have been adjudged to
be liable to the Company, unless a court determines that, despite such
adjudication but in view of all of the circumstances, he is entitled to
indemnification of such expenses. Notwithstanding the foregoing, to the extent
that a director or officer has been successful, on the merits or otherwise, he
will be indemnified by the Company against all expenses (including attorneys'
fees) incurred in connection therewith. Expenses shall be advanced to a director
or officer at his request, provided that he undertakes to repay the amount
advanced if it is ultimately determined that he is not entitled to
indemnification for such expenses.

     Indemnification is required to be made unless the Company determines that
the applicable standard of conduct required for indemnification has not been
met. In the event of a determination by the Company that the director or officer
did not meet the applicable standard of conduct required for indemnification, or
if the Company fails to make an indemnification payment within 60 days after
such payment is claimed by such person, such person is permitted to petition the
court to make an independent determination as to whether such person is entitled
to indemnification. As a condition precedent to the right of indemnification,
the director or officer must give the Company notice of the action for which
indemnity is sought and the Company has the right to participate in such action
or assume the defense thereof.

     Article X of the Company's Restated Certificate of Incorporation further
provides that the indemnification provided therein is not exclusive, and
provides that in the event that the Delaware General Corporation Law is amended
to expand the indemnification permitted to directors or officers the Company
must indemnify those persons to the fullest extent permitted by such law as so
amended.



                                      -2-
<PAGE>



     Section 145 of the Delaware General Corporation Law provides that a
corporation has the power to indemnify a director, officer, employee, or agent
of the corporation and certain other persons serving at the request of the
corporation in related capacities against amounts paid and expenses incurred in
connection with an action or proceeding to which he is or is threatened to be
made a party by reason of such position, if such person shall have acted in good
faith and in a manner he reasonably believed to be in or not opposed to the best
interests of the corporation, and, in any criminal proceeding, if such person
had no reasonable cause to believe his conduct was unlawful; provided that, in
the case of actions brought by or in the right of the corporation, no
indemnification shall be made with respect to any matter as to which such person
shall have been adjudged to be liable to the corporation unless and only to the
extent that the adjudicating court determines that such indemnification is
proper under the circumstances.

     The Company maintains a general liability insurance policy which covers
certain liabilities of directors and officers of the Company arising out of
claims based on acts or omissions in their capacities as directors or officers.

     ITEM 7. EXEMPTION FROM REGISTRATION CLAIMED.

     Not applicable.

     ITEM 8. EXHIBITS.

     The Exhibit Index immediately preceding the exhibits is incorporated herein
by reference.

     ITEM 9. UNDERTAKINGS.

     1. ITEM 512(a) OF REGULATION S-K. 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;

               (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; and

               (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 paragraphs (i) and (ii) do not apply if the
          information required to be included in a post-effective amendment by
          those paragraphs is contained in periodic reports filed with or
          furnished to the Commission by the registrant pursuant to Section 13
          or Section 15(d) of the Exchange Act that are incorporated by
          reference in the registration statement.


                                      -3-
<PAGE>


          (2) That, for the purpose of determining any liability under the
     Securities Act, 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.

     2. ITEM 512(b) OF REGULATION S-K. The undersigned registrant hereby
undertakes that, for purposes of determining any liability under the Securities
Act, each filing of the registrant's annual report pursuant to Section 13(a) or
Section 15(d) of the Exchange Act that is incorporated by reference in the
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.

     3. ITEM 512(h) OF REGULATION S-K. Insofar as indemnification for
liabilities arising under the Securities Act 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 Securities 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
Securities Act and will be governed by the final adjudication of such issue.



                                      -4-
<PAGE>



                                   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 Charlestown, Massachusetts, on this 9th day of July, 2001.

                                       BIOTRANSPLANT INCORPORATED

                                       By: /s/ Elliot Lebowitz
                                          -------------------------------------
                                          Elliot Lebowitz
                                          President and Chief Executive Officer

                        POWER OF ATTORNEY AND SIGNATURES

     We, the undersigned officers and directors of BioTransplant Incorporated,
hereby severally constitute and appoint Elliot Lebowitz and Richard V. Capasso,
and each of them singly, our true and lawful attorneys with full power to them,
and each of them singly, to sign for us and in our names in the capacities
indicated below, the registration statement on Form S-8 filed herewith and any
and all subsequent amendments to said registration statement, and generally to
do all such things in our names and on our behalf in our capacities as officers
and directors to enable BioTransplant Incorporated to comply with the provisions
of the Securities Act of 1933, as amended, and all requirements of the
Securities and Exchange Commission, hereby ratifying and confirming our
signatures as they may be signed by our said attorneys, or any of them, to said
registration statement and any and all amendments thereto.

     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                                TITLE                             DATE
<S>                                   <C>                                    <C>

/s/ Elliot Lebowitz                   Chief Executive Officer
-------------------------             and Director
Elliot Lebowitz                       (Principal executive officer)            July 9, 2001

/s/ Walter C. Ogier
-------------------------             President, Chief Operating
Walter C. Ogier                       Officer and Director                     July 9, 2001

/s/ Richard V. Capasso                Vice President, Finance and
-------------------------             Treasurer (Principal financial
Richard V. Capasso                    and accounting officer)                  July 9, 2001

/s/ James C. Foster
-------------------------
James C. Foster                       Director                                 July 9, 2001


-------------------------
Daniel O. Hauser                      Director                                          2001
                                                                               ---------,

</TABLE>


                                      -5-

<PAGE>


<TABLE>
<CAPTION>
       SIGNATURE                                TITLE                             DATE
<S>                                   <C>                                   <C>

/s/ Arnold L. Oronsky
-------------------------
Arnold L. Oronsky                     Director                                 July 9, 2001

/s/ Michael S. Perry
-------------------------
Michael S. Perry                      Director                                 July 9, 2001

/s/ Susan M. Racher
-------------------------
Susan M. Racher                       Director                                 July 9, 2001

</TABLE>


                                      -6-

<PAGE>






                                INDEX TO EXHIBITS

NUMBER     DESCRIPTION
4.1(1)     Restated Certificate of Incorporation of the Registrant, as amended
           to date
4.2(2)     By-Laws of the Registrant, as amended to date
5.1        Opinion of Hale and Dorr LLP, counsel to the Registrant
23.1       Consent of Hale and Dorr LLP
           (included in Exhibit 5.1)
23.2       Consent of Arthur Andersen LLP
23.3       Consent of PricewaterhouseCoopers LLP
24.1       Power of attorney (included on the signature pages of this
           registration statement)

------------
(1) Incorporated herein by reference from the Registrant's Form 8-K dated
    July 18, 2000 (File No. 000-28324).
(2) Incorporated herein by reference to the Registrant's Registration Statement
    on Form S-1, as amended (File No. 333-02144).



                                      -7-
[{"type": "S-8", "sequence": "1", "filename": "a2052882zs-8.txt", "description": "FORM S-8", "secsgml_size_bytes": 20271}]
{"company-data": {"conformed-name": "BIOTRANSPLANT INC", "cik": "0000880259", "assigned-sic": "2834", "irs-number": "043119555", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-64816", "film-number": "1677826"}, "business-address": {"street1": "BUILDING 75, 3RD AVENUE", "street2": "BLDG 96 13TH ST", "city": "CHARLESTOWN", "state": "MA", "zip": "02129", "phone": "6172415200"}}
As filed with the Securities and Exchange Commission on July 10, 2001

                                                      Registration No. 333-_____
================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                      ------------------------------------

                                    FORM S-8

                          REGISTRATION STATEMENT UNDER
                           THE SECURITIES ACT OF 1933

                           BIOTRANSPLANT INCORPORATED
             (Exact Name of Registrant as Specified in Its Charter)

              DELAWARE                                      04-3119555
     (State or Other Jurisdiction of                     (I.R.S. Employer
     Incorporation or Organization)                      Identification No.)

   CHARLESTOWN NAVY YARD
 BUILDING 75, THIRD AVENUE
CHARLESTOWN, MASSACHUSETTS                                     02129
(Address of Principal Executive Offices)                     (Zip Code)

               ELIGIX, INC. 1997 EQUITY INCENTIVE PLAN, AS AMENDED
                                       AND
       ELIGIX, INC. AMENDED AND RESTATED MANAGEMENT EQUITY INCENTIVE PLAN
                            (Full Title of the Plans)

                              ELLIOT LEBOWITZ, Ph.D.
                      PRESIDENT AND CHIEF EXECUTIVE OFFICER
                           BIOTRANSPLANT INCORPORATED
                              CHARLESTOWN NAVY YARD
                            BUILDING 75, THIRD AVENUE
                        CHARLESTOWN, MASSACHUSETTS 02129
                     (Name and Address of Agent For Service)

                                 (617) 241-5200
          (Telephone Number, Including Area Code, of Agent For Service)

                         CALCULATION OF REGISTRATION FEE
=====================================================================================================
                                           Proposed               Proposed
Title of                                   Maximum                Maximum
Securities to be     Amount to be          Offering Price Per     Aggregate          Amount of
Registered            Registered           Share                  Offering Price     Registration Fee
-----------------------------------------------------------------------------------------------------
Common
Stock, $0.01
par value
per share            1,595,714 shares(1)   $7.01(2)               $11,185,955(2)        $2,797
=====================================================================================================
(1)  Consists of (i) 605,714 shares issuable under the Eligix, Inc. 1997 Equity
     Incentive Plan, as amended and (ii) 990,000 shares issuable under the
     Eligix, Inc. Amended and Restated Management Equity Incentive Plan.

(2)  Estimated solely for the purpose of calculating the registration fee
     pursuant to Rules 457(c) and 457(h) of the Securities Act of 1933, as
     amended, and based upon the average of the high and low prices of the
     Registrant's Common Stock as reported on the Nasdaq National Market on
     July 6, 2001.
PART I
              INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS

     ITEM 1. PLAN INFORMATION.

     The information required by Item 1 is included in documents sent or given
to participants in the plans covered by this registration statement pursuant to
Rule 428(b)(1) of the Securities Act of 1933, as amended (the "Securities Act").

     ITEM 2. REGISTRANT INFORMATION AND EMPLOYEE PLAN ANNUAL INFORMATION.

     The written statement required by Item 2 is included in documents sent or
given to participants in the plans covered by this registration statement
pursuant to Rule 428(b)(1) of the Securities Act.

                                     PART II
               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

     ITEM 3. INCORPORATION OF DOCUMENTS BY REFERENCE.

     The registrant is subject to the informational and reporting requirements
of Sections 13(a), 14, and 15(d) of the Securities Exchange Act of 1934, as
amended (the "Exchange Act"), and in accordance therewith files reports, proxy
statements and other information with the Securities and Exchange Commission
(the "Commission"). The following documents, which are on file with the
Commission, are incorporated in this registration statement by reference:

     (a) The registrant's latest annual report filed pursuant to Section 13(a)
or 15(d) of the Exchange Act or the latest prospectus filed pursuant to Rule
424(b) under the Securities Act that contains audited financial statements for
the registrant's latest fiscal year for which such statements have been filed.

     (b) All other reports filed pursuant to Section 13(a) or 15(d) of the
Exchange Act since the end of the fiscal year covered by the document referred
to in (a) above.

     (c) The description of the securities contained in the registrant's
registration statement on Form 8-A filed under the Exchange Act, including any
amendment or report filed for the purpose of updating such description.

     All documents subsequently filed by the registrant 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 in this registration statement and to be
part hereof from the date of the filing of such documents. Any statement
contained in a document incorporated or deemed to be incorporated by reference
herein shall be deemed to be modified or superseded for the purposes of this
registration statement to the extent that a statement contained herein or in any
other subsequently filed document which also is or is deemed to be incorporated
by reference herein modifies or supersedes such statement. Any statement so
modified or superseded shall not be deemed, except as so modified or superseded,
to constitute a part of this registration statement.

                                      -1-
ITEM 4. DESCRIPTION OF SECURITIES.

     Not applicable.

     ITEM 5. INTERESTS OF NAMED EXPERTS AND COUNSEL.

     Hale and Dorr LLP has opined as to the legality of the securities being
offered by this registration statement. Steven D. Singer, a partner of Hale and
Dorr LLP, serves as Secretary to the registrant.

     ITEM 6. INDEMNIFICATION OF DIRECTORS AND OFFICERS.

     Article IX of the Company's Restated Certificate of Incorporation provides
that no director of the Company shall be personally liable for any monetary
damages for any breach of fiduciary duty as a director, except to the extent
that the Delaware General Corporation Law prohibits the elimination or
limitation of liability of directors for breach of fiduciary duty.

     Article X of the Company's Restated Certificate of Incorporation provides
that a director or officer of the Company (a) shall be indemnified by the
Company against all expenses (including attorneys' fees), judgments, fines, and
amounts paid in settlement incurred in connection with any litigation or other
legal proceeding (other than an action by or in the right of the Company)
brought against him by virtue of his position as a director or officer of the
Company if he acted in good faith and in a manner he reasonably believed to be
in, or not opposed to, the best interests of the Company, and, with respect to
any criminal action or proceeding, had no reasonable cause to believe his
conduct was unlawful and (b) shall be indemnified by the Company against all
expenses (including attorneys' fees) and amounts paid in settlement incurred in
connection with any action by or in the right of the Company brought against him
by virtue of his position as a director or officer of the Company if he acted in
good faith and in a manner he reasonably believed to be in, or not opposed to,
the best interests of the Company, except that no indemnification shall be made
with respect to any matter as to which such person shall have been adjudged to
be liable to the Company, unless a court determines that, despite such
adjudication but in view of all of the circumstances, he is entitled to
indemnification of such expenses. Notwithstanding the foregoing, to the extent
that a director or officer has been successful, on the merits or otherwise, he
will be indemnified by the Company against all expenses (including attorneys'
fees) incurred in connection therewith. Expenses shall be advanced to a director
or officer at his request, provided that he undertakes to repay the amount
advanced if it is ultimately determined that he is not entitled to
indemnification for such expenses.

     Indemnification is required to be made unless the Company determines that
the applicable standard of conduct required for indemnification has not been
met. In the event of a determination by the Company that the director or officer
did not meet the applicable standard of conduct required for indemnification, or
if the Company fails to make an indemnification payment within 60 days after
such payment is claimed by such person, such person is permitted to petition the
court to make an independent determination as to whether such person is entitled
to indemnification. As a condition precedent to the right of indemnification,
the director or officer must give the Company notice of the action for which
indemnity is sought and the Company has the right to participate in such action
or assume the defense thereof.

     Article X of the Company's Restated Certificate of Incorporation further
provides that the indemnification provided therein is not exclusive, and
provides that in the event that the Delaware General Corporation Law is amended
to expand the indemnification permitted to directors or officers the Company
must indemnify those persons to the fullest extent permitted by such law as so
amended.

                                      -2-
Section 145 of the Delaware General Corporation Law provides that a
corporation has the power to indemnify a director, officer, employee, or agent
of the corporation and certain other persons serving at the request of the
corporation in related capacities against amounts paid and expenses incurred in
connection with an action or proceeding to which he is or is threatened to be
made a party by reason of such position, if such person shall have acted in good
faith and in a manner he reasonably believed to be in or not opposed to the best
interests of the corporation, and, in any criminal proceeding, if such person
had no reasonable cause to believe his conduct was unlawful; provided that, in
the case of actions brought by or in the right of the corporation, no
indemnification shall be made with respect to any matter as to which such person
shall have been adjudged to be liable to the corporation unless and only to the
extent that the adjudicating court determines that such indemnification is
proper under the circumstances.

     The Company maintains a general liability insurance policy which covers
certain liabilities of directors and officers of the Company arising out of
claims based on acts or omissions in their capacities as directors or officers.

     ITEM 7. EXEMPTION FROM REGISTRATION CLAIMED.

     Not applicable.

     ITEM 8. EXHIBITS.

     The Exhibit Index immediately preceding the exhibits is incorporated herein
by reference.

     ITEM 9. UNDERTAKINGS.

     1. ITEM 512(a) OF REGULATION S-K. 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;

               (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; and

               (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 paragraphs (i) and (ii) do not apply if the
          information required to be included in a post-effective amendment by
          those paragraphs is contained in periodic reports filed with or
          furnished to the Commission by the registrant pursuant to Section 13
          or Section 15(d) of the Exchange Act that are incorporated by
          reference in the registration statement.

                                      -3-
(2) That, for the purpose of determining any liability under the
     Securities Act, 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.

     2. ITEM 512(b) OF REGULATION S-K. The undersigned registrant hereby
undertakes that, for purposes of determining any liability under the Securities
Act, each filing of the registrant's annual report pursuant to Section 13(a) or
Section 15(d) of the Exchange Act that is incorporated by reference in the
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.

     3. ITEM 512(h) OF REGULATION S-K. Insofar as indemnification for
liabilities arising under the Securities Act 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 Securities 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
Securities Act and will be governed by the final adjudication of such issue.

                                      -4-
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 Charlestown, Massachusetts, on this 9th day of July, 2001.

                                       BIOTRANSPLANT INCORPORATED

                                       By: /s/ Elliot Lebowitz
                                          -------------------------------------
                                          Elliot Lebowitz
                                          President and Chief Executive Officer

                        POWER OF ATTORNEY AND SIGNATURES

     We, the undersigned officers and directors of BioTransplant Incorporated,
hereby severally constitute and appoint Elliot Lebowitz and Richard V. Capasso,
and each of them singly, our true and lawful attorneys with full power to them,
and each of them singly, to sign for us and in our names in the capacities
indicated below, the registration statement on Form S-8 filed herewith and any
and all subsequent amendments to said registration statement, and generally to
do all such things in our names and on our behalf in our capacities as officers
and directors to enable BioTransplant Incorporated to comply with the provisions
of the Securities Act of 1933, as amended, and all requirements of the
Securities and Exchange Commission, hereby ratifying and confirming our
signatures as they may be signed by our said attorneys, or any of them, to said
registration statement and any and all amendments thereto.

     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/ Elliot Lebowitz                   Chief Executive Officer
-------------------------             and Director
Elliot Lebowitz                       (Principal executive officer)            July 9, 2001

/s/ Walter C. Ogier
-------------------------             President, Chief Operating
Walter C. Ogier                       Officer and Director                     July 9, 2001

/s/ Richard V. Capasso                Vice President, Finance and
-------------------------             Treasurer (Principal financial
Richard V. Capasso                    and accounting officer)                  July 9, 2001

/s/ James C. Foster
-------------------------
James C. Foster                       Director                                 July 9, 2001

-------------------------
Daniel O. Hauser                      Director                                          2001
                                                                               ---------,
-5-
SIGNATURE                                TITLE                             DATE
/s/ Arnold L. Oronsky
-------------------------
Arnold L. Oronsky                     Director                                 July 9, 2001

/s/ Michael S. Perry
-------------------------
Michael S. Perry                      Director                                 July 9, 2001

/s/ Susan M. Racher
-------------------------
Susan M. Racher                       Director                                 July 9, 2001
-6-
INDEX TO EXHIBITS

NUMBER     DESCRIPTION
4.1(1)     Restated Certificate of Incorporation of the Registrant, as amended
           to date
4.2(2)     By-Laws of the Registrant, as amended to date
5.1        Opinion of Hale and Dorr LLP, counsel to the Registrant
23.1       Consent of Hale and Dorr LLP
           (included in Exhibit 5.1)
23.2       Consent of Arthur Andersen LLP
23.3       Consent of PricewaterhouseCoopers LLP
24.1       Power of attorney (included on the signature pages of this
           registration statement)

------------
(1) Incorporated herein by reference from the Registrant's Form 8-K dated
    July 18, 2000 (File No. 000-28324).
(2) Incorporated herein by reference to the Registrant's Registration Statement
    on Form S-1, as amended (File No. 333-02144).

                                      -7-