content: <PAGE>   1
                 As filed with the Securities and Exchange Commission
                                 on May 30, 1995
                                                    Registration No. 33-     
  
  ===============================================================================
                           SECURITIES AND EXCHANGE COMMISSION
                                 WASHINGTON, D.C. 20549
  
                                        FORM S-8
  
                              REGISTRATION STATEMENT UNDER
                               THE SECURITIES ACT OF 1933
  
                                 GENETICS INSTITUTE, INC.                   
                   (Exact name of issuer as specified in its charter)
  
                      DELAWARE                               04-2718435     
           (State or other jurisdiction of                (I.R.S. Employer
            incorporation or organization)               Identification No.)
  
            87 CAMBRIDGEPARK DRIVE, CAMBRIDGE, MASSACHUSETTS   02140
                (Address of Principal Executive Offices)     (Zip Code)
  
                                   1991 STOCK OPTION PLAN
                                  (Full title of the plan)
  
                                    MARK G. BORDEN, ESQ.
                                        HALE AND DORR
                                       60 STATE STREET
                                 BOSTON, MASSACHUSETTS  02109  
                           (Name and address of agent for service)
  
                                       (617) 526-6000
                (Telephone number, including area code, of agent for service)
                                                                              
  <TABLE>
                              CALCULATION OF REGISTRATION FEE
  ================================================================================
  <CAPTION>
                                        Proposed   Proposed
         Title of                       maximum    maximum
         securities         Amount      offering   aggregate       Amount of
         to be              to be       price      offering        registration
         registered         registered  per share  price           fee          
         ----------         ----------  ---------  ---------       ------------
         <S>                <C>         <C>        <C>             <C>
         Depositary Shares, 1,300,000   $36.25(1)  $47,125,000(1)  $16,250
         each representing    shares
         one share of 
         Common Stock,
         $.01 par value,
         subject to a call
         option and 
         evidenced by a 
         depositary
         receipt
  - --------------------------------------------------------------------------------
  </TABLE>
  
                            
  <PAGE>   2
  
  <TABLE>
         <S>                       <C>      <C>            <C>          <C>
         Common Stock,
         $.01 par value            (2)      N/A            N/A          (3)
  - --------------------------------------------------------------------------------
  <FN>
         (1)  Estimated solely for the purpose of calculating the
              registration fee, and based upon the average of the
              high and low prices of the Common Stock on the Nasdaq
              National Market on May 25, 1995 in accordance with
              Rules 457(c) and 457(h) of the Securities Act of 1933.
  
         (2)  Such number of shares of Common Stock as are represented 
              by the Depositary Shares registered hereby.
  
         (3)  Because the Common Stock is issued for no consideration, 
              no registration fee is required with respect thereto.
  
  ================================================================================
  </TABLE>
  
  
  
  
  
  
  
                                           -2-
  <PAGE>   3
  
                        Statement of Incorporation by Reference
                        ---------------------------------------
  
                This Registration Statement on Form S-8 incorporates by
           reference the contents of the Registration Statements on Form S-8,
           File Nos. 33-43651, filed by the Registrant on November 5, 1991,
           and 33-63052, filed on May 20, 1993, relating to the Registrant's
           1991 Stock Option Plan.  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
                                           -3-
  
  <PAGE>   4
  
                                       SIGNATURES
  
                Pursuant to the requirements of the Securities Act, 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 Boston, Commonwealth of Massachusetts on the 25th day of May,
           1995.
  
  
                                              GENETICS INSTITUTE, INC.
  
  
  
                                              By: /s/ Gabriel Schmergel     
                                                  ----------------------
                                                  Gabriel Schmergel
                                                  President and Chief 
                                                    Executive Officer
  
  
  
  
                                    POWER OF ATTORNEY
  
                We, the undersigned officers and directors of Genetics
           Institute, Inc. hereby severally constitute Gabriel Schmergel,
           Garen G. Bohlin and Mark G. Borden, 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 behalf in our capacities as officers and directors to
           enable Genetics Institute, Inc. to comply with all requirements of
           the Securities and Exchange Commission, hereby ratifying and
           confirming our signatures as they may be signed by said attorneys,
           or any of them, to said Registration Statement and any and all
           amendments thereto.
  
                WITNESS our hands and common seal on the date set forth
           below.
  
                                           -4-
  <PAGE>   5
  
  <TABLE>
             Pursuant to the requirements of the Securities Act of 1933, this
        Registration Statement has been signed below by the following persons
        in the capacities and on the dates indicated.  
  
  <CAPTION>
  
                Signature              Title                        Date
                ---------              -----                        ----
  
           <S>                      <C>                      <C>
           /s/ Gabriel Schmergel    President, Chief         )
           ----------------------   Executive Officer and    )
           Gabriel Schmergel        Director (Principal      )
                                    Executive Officer)       )
                                                             )
                                                             )
                                                             )
           /s/ Garen G. Bohlin      Executive Vice President )
           ----------------------   (Principal Financial     )
           Garen G. Bohlin          Officer and Principal    )
                                    Accounting Officer)      )
                                                             )
                                                             )
           /s/ James G. Andress     Director                 )
           ----------------------                            )
           James G. Andress                                  )
                                                             )
                                                             )
           /s/ J. Richard Crout     Director                 )
           ----------------------                            )
           J. Richard Crout                                  )
                                                             )
                                                             )
           /s/ Anthony B. Evnin     Director                 )  May 25, 1995
           ----------------------                            )
           Anthony B. Evnin                                  )
                                                             )
                                                             )
           /s/ Fred Hassan          Director                 )
           ----------------------                            )
           Fred Hassan                                       )
                                                             )
                                                             )
           /s/ Robert I. Levy       Director                 )
           ----------------------                            )
           Robert I. Levy                                    )
                                                             )
                                                             )
           /s/ Thomas P. Maniatis   Director                 )
           ----------------------                            )
           Thomas P. Maniatis                                )
                                                             )
                                                             )
           /s/ Benno C. Schmidt     Director                 )
           ----------------------                            )
           Benno C. Schmidt                                  )
  
  </TABLE>
  
  
                                           -5-
  <PAGE>   6
  
  
  <TABLE>
                                       EXHIBIT INDEX
                                       -------------
  <CAPTION>
  
      Exhibit
      Number       Description                                         Page
      -------      -----------                                         ----
        <S>        <C>                                                  <C>
         4.1       Restated Certificate of Incorporation. (1)           --
  
         4.2       Restated By-laws of the Registrant. (2)              --
  
         4.3       Depositary Agreement among Genetics Institute,
                   Inc., American Home Products Corporation,
                   AHP Biotech Holdings, Inc. and The First
                   National Bank of Boston, as Depositary.(1)           --
  
         5.1       Opinion of Hale and Dorr.                              
  
        23.1       Consent of Hale and Dorr (included in Exhibit 5.1).  --
  
        23.2       Consent of Arthur Andersen LLP.
  
        23.3       Consent of Coopers & Lybrand L.L.P.                    
  
        24.1       Power of Attorney (included in the signature 
                   pages of this Registration Statement).               --
  
  
  
  
  
  
  
  
  
  <FN>
  
           ______________________
           (1)  Filed as an exhibit to the Company's Annual Report on
                Form 10-K for the year ended November 30, 1991 (File No. 0-
                14587) on February 28, 1992 and incorporated herein by
                reference.
  
           (2)  Filed as an exhibit to the Company's Quarterly Report on
                Form 10-Q/A for the quarter ended March 31, 1995 
                (File No. 0-14587) on May 26, 1995 and incorporated herein by
                reference.
  
  </TABLE>
  
  
                                           -5-
metadata_documents: [{"type": "S-8", "sequence": "1", "description": "FORM S-8", "secsgml_size_bytes": 11424}]
metadata_filer: {"company-data": {"conformed-name": "GENETICS INSTITUTE INC", "cik": "0000731336", "assigned-sic": "2836", "irs-number": "042718435", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "033-59669", "film-number": "95543102"}, "business-address": {"street1": "87 CAMBRIDGE PK DR", "city": "CAMBRIDGE", "state": "MA", "zip": "02140", "phone": "6178761170"}, "mail-address": {"street1": "87 CAMBRIDGE PARK DRIVE", "city": "CAMBRIDGE", "state": "MA", "zip": "02140"}}
text: 1
                 As filed with the Securities and Exchange Commission
                                 on May 30, 1995
                                                    Registration No. 33-     
  
  ===============================================================================
                           SECURITIES AND EXCHANGE COMMISSION
                                 WASHINGTON, D.C. 20549
  
                                        FORM S-8
  
                              REGISTRATION STATEMENT UNDER
                               THE SECURITIES ACT OF 1933
  
                                 GENETICS INSTITUTE, INC.                   
                   (Exact name of issuer as specified in its charter)
  
                      DELAWARE                               04-2718435     
           (State or other jurisdiction of                (I.R.S. Employer
            incorporation or organization)               Identification No.)
  
            87 CAMBRIDGEPARK DRIVE, CAMBRIDGE, MASSACHUSETTS   02140
                (Address of Principal Executive Offices)     (Zip Code)
  
                                   1991 STOCK OPTION PLAN
                                  (Full title of the plan)
  
                                    MARK G. BORDEN, ESQ.
                                        HALE AND DORR
                                       60 STATE STREET
                                 BOSTON, MASSACHUSETTS  02109  
                           (Name and address of agent for service)
  
                                       (617) 526-6000
                (Telephone number, including area code, of agent for service)
                                                                              
  
                              CALCULATION OF REGISTRATION FEE
  ================================================================================
  Proposed   Proposed
         Title of                       maximum    maximum
         securities         Amount      offering   aggregate       Amount of
         to be              to be       price      offering        registration
         registered         registered  per share  price           fee          
         ----------         ----------  ---------  ---------       ------------
  Depositary Shares, 1,300,000   $36.25(1)  $47,125,000(1)  $16,250
         each representing    shares
         one share of 
         Common Stock,
         $.01 par value,
         subject to a call
         option and 
         evidenced by a 
         depositary
         receipt
  - --------------------------------------------------------------------------------
  2
  Common Stock,
         $.01 par value            (2)      N/A            N/A          (3)
  - --------------------------------------------------------------------------------
  (1)  Estimated solely for the purpose of calculating the
              registration fee, and based upon the average of the
              high and low prices of the Common Stock on the Nasdaq
              National Market on May 25, 1995 in accordance with
              Rules 457(c) and 457(h) of the Securities Act of 1933.
  
         (2)  Such number of shares of Common Stock as are represented 
              by the Depositary Shares registered hereby.
  
         (3)  Because the Common Stock is issued for no consideration, 
              no registration fee is required with respect thereto.
  
  ================================================================================
  -2-
  3
  
                        Statement of Incorporation by Reference
                        ---------------------------------------
  
                This Registration Statement on Form S-8 incorporates by
           reference the contents of the Registration Statements on Form S-8,
           File Nos. 33-43651, filed by the Registrant on November 5, 1991,
           and 33-63052, filed on May 20, 1993, relating to the Registrant's
           1991 Stock Option Plan.  
  
                                           -3-
  4
  
                                       SIGNATURES
  
                Pursuant to the requirements of the Securities Act, 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 Boston, Commonwealth of Massachusetts on the 25th day of May,
           1995.
  
                                              GENETICS INSTITUTE, INC.
  
                                              By: /s/ Gabriel Schmergel     
                                                  ----------------------
                                                  Gabriel Schmergel
                                                  President and Chief 
                                                    Executive Officer
  
                                    POWER OF ATTORNEY
  
                We, the undersigned officers and directors of Genetics
           Institute, Inc. hereby severally constitute Gabriel Schmergel,
           Garen G. Bohlin and Mark G. Borden, 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 behalf in our capacities as officers and directors to
           enable Genetics Institute, Inc. to comply with all requirements of
           the Securities and Exchange Commission, hereby ratifying and
           confirming our signatures as they may be signed by said attorneys,
           or any of them, to said Registration Statement and any and all
           amendments thereto.
  
                WITNESS our hands and common seal on the date set forth
           below.
  
                                           -4-
  5
  
             Pursuant to the requirements of the Securities Act of 1933, this
        Registration Statement has been signed below by the following persons
        in the capacities and on the dates indicated.
  Signature              Title                        Date
                ---------              -----                        ----
  /s/ Gabriel Schmergel    President, Chief         )
           ----------------------   Executive Officer and    )
           Gabriel Schmergel        Director (Principal      )
                                    Executive Officer)       )
                                                             )
                                                             )
                                                             )
           /s/ Garen G. Bohlin      Executive Vice President )
           ----------------------   (Principal Financial     )
           Garen G. Bohlin          Officer and Principal    )
                                    Accounting Officer)      )
                                                             )
                                                             )
           /s/ James G. Andress     Director                 )
           ----------------------                            )
           James G. Andress                                  )
                                                             )
                                                             )
           /s/ J. Richard Crout     Director                 )
           ----------------------                            )
           J. Richard Crout                                  )
                                                             )
                                                             )
           /s/ Anthony B. Evnin     Director                 )  May 25, 1995
           ----------------------                            )
           Anthony B. Evnin                                  )
                                                             )
                                                             )
           /s/ Fred Hassan          Director                 )
           ----------------------                            )
           Fred Hassan                                       )
                                                             )
                                                             )
           /s/ Robert I. Levy       Director                 )
           ----------------------                            )
           Robert I. Levy                                    )
                                                             )
                                                             )
           /s/ Thomas P. Maniatis   Director                 )
           ----------------------                            )
           Thomas P. Maniatis                                )
                                                             )
                                                             )
           /s/ Benno C. Schmidt     Director                 )
           ----------------------                            )
           Benno C. Schmidt                                  )
  -5-
  6
  
                                       EXHIBIT INDEX
                                       -------------
  Exhibit
      Number       Description                                         Page
      -------      -----------                                         ----
  4.1       Restated Certificate of Incorporation. (1)           --
  
         4.2       Restated By-laws of the Registrant. (2)              --
  
         4.3       Depositary Agreement among Genetics Institute,
                   Inc., American Home Products Corporation,
                   AHP Biotech Holdings, Inc. and The First
                   National Bank of Boston, as Depositary.(1)           --
  
         5.1       Opinion of Hale and Dorr.                              
  
        23.1       Consent of Hale and Dorr (included in Exhibit 5.1).  --
  
        23.2       Consent of Arthur Andersen LLP.
  
        23.3       Consent of Coopers & Lybrand L.L.P.                    
  
        24.1       Power of Attorney (included in the signature 
                   pages of this Registration Statement).               --
  ______________________
           (1)  Filed as an exhibit to the Company's Annual Report on
                Form 10-K for the year ended November 30, 1991 (File No. 0-
                14587) on February 28, 1992 and incorporated herein by
                reference.
  
           (2)  Filed as an exhibit to the Company's Quarterly Report on
                Form 10-Q/A for the quarter ended March 31, 1995 
                (File No. 0-14587) on May 26, 1995 and incorporated herein by
                reference.
  -5-