Exhibit 99.1


Investors:                                        Media:
ImClone Systems Incorporated                      Abernathy MacGregor
Andrea F. Rabney                                  Andrew Merrill or David Pitts
(646) 638-5058                                    (212) 371-5999
Stefania A. Bethlen
(646) 638-5046

For Immediate Release
---------------------


             IMCLONE SYSTEMS ANNOUNCES BOARD AND MANAGEMENT CHANGES

New York, NY - April 29, 2003 -- ImClone Systems Incorporated (Nasdaq: IMCLE)
announced today that, in connection with a previously disclosed internal review
related to withholding tax liabilities associated with the exercise of certain
options and warrants, the following Board and executive changes are effective
immediately:

     o    Robert F. Goldhammer has resigned as Chairman of the Board. Mr.
          Goldhammer has also decided not to stand for re-election to the Board
          of Directors at the next annual shareholders' meeting. Mr. Goldhammer
          will serve out his current term as a Director.

     o    Harlan W. Waksal, M.D., currently President and Chief Executive
          Officer of ImClone, has resigned from these positions. Dr. Waksal has
          been named Chief Scientific Officer of the Company, with
          responsibility for research, clinical, regulatory, quality assurance
          and manufacturing.

     o    Daniel S. Lynch, currently Senior Vice President, Finance, and Chief
          Financial Officer, has been named Senior Vice President, Chief
          Administrative Officer and Chief Financial Officer. In addition to his
          current responsibilities for finance, control and compliance, human
          resources, communications, and information technology, Mr. Lynch will
          assume responsibility for the sales and marketing, legal and business
          development departments. Mr. Lynch will serve as acting Chief
          Executive Officer until a permanent Chief Executive Officer has been
          named.

In addition, ImClone Systems issued the following statement: "The Company's
current difficulties led the independent members of the Board of Directors to
conclude that a change in leadership was appropriate. The Company has commenced
a search for a permanent Chief Executive Officer. ImClone Systems will continue
to benefit from Harlan Waksal's scientific leadership in his new role as Chief
Scientific Officer."

ImClone Systems remains committed to finalizing the review of the circumstances
relating to the previously disclosed withholding tax issues and to filing the
Company's annual report on Form 10-K as soon as possible.


About ImClone Systems Incorporated
----------------------------------

ImClone Systems Incorporated is committed to advancing oncology care by
developing a portfolio of targeted biologic treatments, designed to address the
medical needs of patients with a variety of cancers. The Company's three
programs include growth factor blockers, cancer vaccines and angiogenesis
inhibitors. ImClone Systems' strategy is to become a fully integrated
biopharmaceutical company, taking its development programs from the research
stage to the market. ImClone Systems is headquartered in New York City with
additional administration and manufacturing facilities in Somerville, New
Jersey.

The matters discussed in this news release may include forward-looking
statements which involve potential risks and uncertainties. Important factors
that may cause actual results to differ materially include, but are not limited
to, the risks and uncertainties associated with completing pre-clinical and
clinical trials of the company's compounds that demonstrate such compounds'
safety and effectiveness; obtaining additional financing to support the
company's operations; obtaining and maintaining regulatory approval for such
compounds and complying with other governmental regulations applicable to the
company's business; obtaining the raw materials necessary in the development of
such compounds; consummating and maintaining collaborative arrangements with
corporate partners for product development; achieving milestones under
collaborative arrangements with corporate partners; developing the capacity to
manufacture, market and sell the company's products, either directly or with
collaborative partners; developing market demand for and acceptance of such
products; competing effectively with other pharmaceutical and biotechnological
products; obtaining adequate reimbursement from third party payers; attracting
and retaining key personnel; legal costs and the outcome of outstanding legal
proceedings and investigations; obtaining patent protection for discoveries and
risks associated with commercial limitations imposed by patents owned or
controlled by third parties. The company does not undertake any obligation to
update any forward-looking statements, whether as a result of new information,
future events or otherwise.


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