Imclone Systems POS AM Prospectus update (post-effective amendment)

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Exhibit 23.1

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

The Board of Directors
ImClone Systems Incorporated:

        We consent to the use of our reports dated March 15, 2005, with respect to the consolidated balance sheets of ImClone Systems Incorporated as of December 31, 2004 and 2003, and the related consolidated statements of operations, stockholders' equity (deficit) and comprehensive income (loss), and cash flows for each of the years in the three-year period ended December 31, 2004, management's assessment of the effectiveness of internal control over financial reporting as of December 31, 2004, and the effectiveness of internal control over financial reporting as of December 31, 2004, incorporated herein by reference and to the reference to our firm under the heading "Experts" in the prospectus.

/s/ KPMG LLP

Princeton, New Jersey
July 21, 2005

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CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM