EXHIBIT 99.9

                            CERTIFICATION PURSUANT TO
                             18 U.S.C. SECTION 1350,
                             AS ADOPTED PURSUANT TO

                  SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

            In connection with the Annual Report of ImClone Systems Incorporated
(the "Company") on Form 10-K for the period ended December 31, 2002 as filed
with the Securities and Exchange Commission on the date hereof (the "Report"),
I, Daniel S. Lynch, Senior Vice President and Chief Administrative Officer,
acting Chief Executive Officer of the Company, certify, pursuant to 18 U.S.C.
Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of
2002, that:

(1)   The Report fully complies with the requirements of Section 13(a) or 15(d)
      of the Securities Exchange Act of 1934; and

(2)   The information contained in the Report fairly presents, in all material
      respects, the financial condition and results of operations of the
      Company.

                                            /s/ Daniel S. Lynch
                                            ------------------------------------
                                            Daniel S. Lynch
                                            Acting Chief Executive Officer

June 23, 2003