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                                                                     Exhibit 3.3

                   [COMMONWEALTH OF MASSACHUSETTS LETTERHEAD]


                                                          FEDERAL IDENTIFICATION
                                                          No. 04 2726691


                             ARTICLES OF AMENDMENT       
                     GENERAL LAWS, CHAPTER 156B, SECTION 72

We  Mitchel Sayare,                                        President and
    Jonathan L. Kravetz                                    Clerk/of

                                ImmunocGen, Inc.
- -------------------------------------------------------------------------------
                          (EXACT Name of Corporation)

located at: 128 Sidney Street, Cambridge, MA 02139
            -------------------------------------------------------------------
                     (MASSACHUSETTS Address of Corporation)

do hereby certify that these ARTICLES OF AMENDMENT affecting Articles NUMBERED:
                                       3
- -------------------------------------------------------------------------------
      (Number those articles 1, 2, 3, 4, 5 and/or 6 being amended hereby)

of the Articles of Organization were duly adopted at a meeting held on June 6,
1996, by vote of:

12,583,631 shares of       Common          out of 15,530,355 shares outstanding,
- ----------           ---------------------        ----------
                     type, class & series, 
                           (if any)

           shares of                       out of            shares outstanding,
- ----------           ---------------------       -----------
                     type, class & series, 
                           (if any)

           shares of                       out of            shares outstanding,
- ----------           ---------------------        ----------
                     type, class & series, 
                           (if any)

CROSS OUT  being at least a majority of each type, class or series outstanding
INAPPLI-   and entitled to vote thereon-
CABLE      
CLAUSE


 C   / /
 P   / / 
 M   / /    1  For amendments adopted pursuant to Chapter 156B, Section 70.
R.A. / /    2  For amendments adopted pursuant to Chapter 156B, Section 71.
             
            Note: if the space provided under any Amendment or item on this form
            is insufficient, additions shall be set forth on separate 8-1/2 x 11
            sheets of paper leaving a left-hand margin of at least 1 inch for
            binding. Additions to more than one Amendment may be continued on a
            single sheet so long as each Amendment requiring each such addition
            is clearly indicated.


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To CHANGE the number of shares and the par value (if any) of any type, class or
series of stock which the corporation is authorized to issue, fill in the 
following:

The total presently authorized is:

                            WITHOUT PAR VALUE STOCKS



TYPE                                         NUMBER OF SHARES
                                          
COMMON:.....................................  
PREFERRED:..................................  


                             WITH PAR VALUE STOCKS



TYPE                                         NUMBER OF SHARES          PAR VALUE
                                                                 
COMMON:.....................................    20,000,000                $.01
PREFERRED: Series A.........................          None                
           Series B.........................          None
           Series C.........................       122,555                $.01
           Series D.........................       154,525                $.01


CHANGE the total authorized to:

                             WITHOUT PAR VALUE STOCKS



TYPE                                         NUMBER OF SHARES
                                          
COMMON:.....................................  
PREFERRED:..................................  

 
                             WITH PAR VALUE STOCKS



TYPE                                         NUMBER OF SHARES          PAR VALUE
                                                                 
COMMON:.....................................    30,000,000                $.01
PREFERRED: Series A.........................          None                
           Series B.........................          None
           Series C.........................       122,555                $.01
           Series D.........................       154,525                $.01

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The foregoing amendment will become effective when these articles of amendment
are filed in accordance with Chapter 156B, Section 6 of The General Laws unless
these articles specify, in accordance with the vote adopting the amendment, a
later effective date not more than thirty days after such filing, in which
event the amendment will become effective on such later date.

                              LATER EFFECTIVE DATE: _________________________


IN WITNESS WHEREOF AND UNDER THE PENALTIES OF PERJURY, we have hereunto signed
our names this    sixth    day of June    , in the year 1996.


          /s/  Mitchel Sayare                             President
_________________________________________________________
               Mitchel Sayare


          /s/  Jonathan L. Kravetz                        Clerk
_________________________________________________________
               Jonathan L. Kravetz
  
                    
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                         THE COMMONWEALTH OF MASSACHUSETTS


                                ARTICLES OF AMENDMENT
                       GENERAL LAWS, CHAPTER 156B, SECTION 72
                       ______________________________________
                       ______________________________________


                       I hereby approve the within articles of
                       amendment and, the filing fee in the
                       amount of $______ having been paid, said
                       articles are deemed to have been filed
                       with me this ____ day of _____________,
                       19__.



                                 MICHAEL J. CONNOLLY
                                 Secretary of State








                      To be filled in by Corporation

                      PHOTOCOPY OF ARTICLES OF AMENDMENT TO BE SENT




                 TO:    Anne T. Leland, Legal Assistant
                     ______________________________________________________
                          
                        Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C.
                     ______________________________________________________

                        One Financial Center, Boston, MA 02111
                     ______________________________________________________
     
                                       617 542 6000
                     Telephone: ___________________________________