Exhibit 4.3

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                                 [CELGENE LOGO]
       NUMBER                                                           SHARES
                               CELGENE CORPORATION
              INCORPORATED UNDER THE LAWS OF THE STATE OF DELAWARE

THIS CERTIFICATE IS TRANSFERABLE                              COMMON STOCK
         IN NEW YORK, NY                                    CUSIP 151020 10 4

                                                             SEE REVERSE FOR
THIS CERTIFIES THAT                                        CERTAIN DEFINITIONS

                                    SPECIMEN




is the owner of

             FULLY PAID AND NON-ASSESSABLE SHARES OF COMMON STOCK,
                          PAR VALUE $.01 PER SHARE, OF
------------------------------ CELGENE CORPORATION -----------------------------
transferable on the books of the Corporation by the holder hereof in person or
by duly authorized attorney, upon surrender of this certificate properly
endorsed.
     This certificate is not valid until countersigned by the Transfer Agent and
registered by the Registrar.
     WITNESS the facsimile seal of the Corporation and the facsimile signatures
of its duly authorized officers.
Dated

                                    COUNTERSIGNED AND REGISTERED
                                         AMERICAN STOCK TRANSFER & TRUST COMPANY
                                                    NEW YORK      TRANSFER AGENT
                                                                   AND REGISTRAR

                                    BY

                                                            AUTHORIZED SIGNATURE



                                 [CELGENE SEAL]


CHAIRMAN AND CHIEF EXECUTIVE OFFICER       CHIEF FINANCIAL OFFICER AND SECRETARY

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<PAGE>

   The following abbreviations, when used in the inscription on the face of this
certificate,  shall  be  construed  as  though  they  were  written  out in full
according to applicable laws or regulations:

   TEN COM --as tenants in common        UNIF GIFT MIN ACT--.....Custodian......
   TEN ENT --as tenants by the entireties                  (Cust)        (Minor)
   JT TEN  --as joint tenants with right of        under Uniform Gifts to Minors
             survivorship and not as tenants       Act...............
             in common                                    (State)

    Additional abbreviations may also be used though not in the above list.


          For Value Received, ________hereby sell, assign and transfer unto
PLEASE INSERT SOCIAL SECURITY OR OTHER
   IDENTIFYING NUMBER OF ASSIGNEE
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  PLEASE PRINT OR TYPEWRITE NAME AND ADDRESS, INCLUDING ZIP CODE, OF ASSIGNEE

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--------------------------------------------------------------------------Shares
of the  capital  stock  represented  by the  within  Certificate,  and do hereby
irrevocably constitute and appoint

------------------------------------------------------------------------Attorney
to transfer  the said stock on the books of the within  named  Corporation  with
full power of substitution in the premises.

Dated
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               THE SIGNATURE TO THIS ASSIGNMENT MUST CORRESPOND WITH THE NAME AS
               WRITTEN  UPON THE FACE OF THE  CERTIFICATE  IN EVERY  PARTICULAR,
       NOTICE: WITHOUT ALTERATION OR ENLARGEMENT OR ANY CHANGE WHATEVER.


   This  certificate  also  evidences  and entitles the holder hereof to certain
rights set forth in a Rights Agreement between Celgene  Corporation and American
Stock  Transfer & Trust  Company  dated as of  September  16, 1996 (the  "Rights
Agreement"),  the terms of which are hereby incorporated herein by reference and
a copy of  which  is on file  at the  principal  executive  offices  of  Celgene
Corporation. Under certain circumstances,  as set forth in the Rights Agreement,
such Rights will be  evidenced  by separate  certificates  and will no longer be
evidenced by this  certificate.  Celgene  Corporation will mail to the holder of
this certificate a copy of the Rights Agreement  without charge after receipt of
a written request therefor.  Under certain circumstances set forth in the Rights
Agreement,  Rights  issued to or held by any  Person  who is,  was or becomes an
Acquiring Person or an Affiliate or Associate  thereof (as defined in the Rights
Agreement) and certain related persons,  whether  currently held by or on behalf
of such Person or by any subsequent holder, may become null and void.