EXHIBIT 32.1


                            CERTIFICATION PURSUANT TO
                               18 U.S.C. SS.1350,
                             AS ADOPTED PURSUANT TO
                  SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the accompanying Annual Report on Form 10K of Celgene
Corporation ("the Company") for the period ended December 31, 2003 ("the
Periodic Report"), I, John W. Jackson, Chief Executive Officer of the Company,
hereby certify pursuant to 18 U.S.C. Section 1350, as adopted pursuant to
Section 906 of the Sarbanes-Oxley Act of 2002, to the best of my knowledge that
the Periodic Report fully complies with the requirements of Section 13(a) or
15(d) of the Securities Exchange Act of 1934 and that the information contained
in the Periodic Report fairly presents, in all material respects, the financial
condition and results of operations of the Company.


Date: March 12, 2004                                     /s/ John W. Jackson
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                                                         John W. Jackson
                                                         Chief Executive Officer