EXHIBIT 99(a)(1)(i)


This announcement is neither an offer to purchase nor a solicitation of an
offer to sell Shares (as defined below). The Offer (as defined below) is made
solely by the Offer to Purchase, dated September 28, 2001, and the related
Letter of Transmittal, and any amendments or supplements thereto. The Offer
is not being made to (nor will tenders be accepted from or on behalf of)
holders of Shares in any jurisdiction in which the making of the Offer or the
acceptance thereof would not be in compliance with the laws of such
jurisdiction. In any jurisdiction where the securities, blue sky or other
laws require the Offer to be made by a licensed broker or dealer, the Offer
will be deemed to be made on behalf of the Purchaser by Lehman Brothers Inc.
or by one or more registered brokers or dealers that are licensed under the
laws of such jurisdiction.

                      Notice of Offer to Purchase for Cash

                    Up to 14,392,003 Shares of Common Stock

                                       of

                          ImClone Systems Incorporated

                                       at

                              $70.00 Net Per Share

                                       by

                     Bristol-Myers Squibb Biologics Company
             (a wholly owned subsidiary of Bristol-Myers Squibb Company)

Bristol-Myers Squibb Biologics Company, a Delaware corporation (the
"Purchaser") and a wholly owned subsidiary of Bristol-Myers Squibb Company, a
Delaware corporation ("Parent"), is offering to purchase up to 14,392,003
shares ("Shares") of common stock, par value $.001 per share, of ImClone
Systems Incorporated, a Delaware corporation (the "Company"), at a price of
$70.00 per Share, net to the seller in cash (the "Offer Price"), upon the
terms and subject to the conditions set forth in the Offer to Purchase and in
the related Letter of Transmittal (which, together with any amendments or
supplements thereto, constitute the "Offer"). Shares to be purchased by the
Purchaser in the Offer include Shares tendered upon the conditional exercise
of exercisable options to purchase Shares having exercise prices below $70.00
per Share held by present or former employees and directors of the Company.
The Offer is being made pursuant to the Acquisition Agreement, dated as of
September 19, 2001 (the "Acquisition Agreement"), among the Purchaser, Parent
and the Company. The Acquisition Agreement was entered into in connection
with the transactions contemplated by the Development, Promotion,
Distribution and Supply Agreement, dated as of September 19, 2001 (the
"Commercial Agreement"), among Parent, E.R. Squibb & Sons, L.L.C., a limited
liability company under the laws of Delaware ("E.R. Squibb") and a wholly
owned subsidiary of Parent, and the Company. Pursuant to the Commercial
Agreement, Parent and E.R. Squibb were granted certain co-development,
co-promotion and distribution rights with respect to the Company's leading
product, and incurred certain obligations with respect to the co-development,
co-promotion and distribution of this product. In addition to the Acquisition
Agreement and the Commercial Agreement, Parent, the Purchaser and the Company
have entered into a Stockholder Agreement, dated as of September 19, 2001
(the "Stockholder Agreement"), pursuant to which



Parent, the Purchaser and the Company have agreed to various arrangements
regarding the respective rights and obligations of Parent, the Purchaser and
the Company with respect to, among other things, the ownership of Shares by
Parent and the Purchaser. The purpose of the Offer is to enable Parent and
the Purchaser to acquire a significant equity interest in the Company in
connection with the transactions contemplated by the Commercial Agreement.
After the completion of the purchase of 14,392,003 Shares pursuant to the
Offer, the Purchaser will own approximately 19.9% of the currently
outstanding Shares and will have the right to nominate two directors to the
twelve-member board of directors of the Company. The purpose of the Offer is
not to acquire or influence control of the business of the Company other than
to the extent contemplated by the Commercial Agreement and the Stockholder
Agreement and other than as is inherent in having the right to nominate two
of twelve directors to the board of directors. See Section 12, "Purpose of
the Offer; the Acquisition Agreement; the Stockholder Agreement; the
Commercial Agreement; the Confidentiality Agreement; Plans for the Company"
of the Offer to Purchase. THE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT
12:00 MIDNIGHT, NEW YORK CITY TIME, ON FRIDAY, OCTOBER 26, 2001, UNLESS THE
OFFER IS EXTENDED.

The Offer is conditioned upon (1) the conditions to the Purchaser's
obligation to purchase Shares in the Offer set forth in the Acquisition
Agreement having been satisfied or waived and (2) any waiting period under
the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended (the
"HSR Act"), applicable to the purchase of Shares pursuant to the Offer having
expired or been terminated. The Offer is not conditioned upon the valid
tender of any minimum number of Shares.

Upon the terms and subject to the conditions of the Offer, if more than
14,392,003 Shares are validly tendered and not properly withdrawn prior to
the Expiration Date (as defined below), the Purchaser will accept such Shares
for payment on a pro rata basis (with adjustments to avoid the purchase of
fractional Shares) from each stockholder who has validly tendered Shares in
the Offer based on the number of Shares validly tendered by each stockholder
prior to the Expiration Date and not properly withdrawn. In the event that
proration of tendered Shares is required, the Purchaser shall determine the
proration factor as soon as practicable following the Expiration Date.
Because of the time required to determine the precise number of Shares
validly tendered and not properly withdrawn prior to the Expiration Date, the
Purchaser does not expect that it will be able to announce the final results
of such proration or pay for any Shares until approximately four trading days
on the Nasdaq National Market after the Expiration Date. Stockholders may
obtain such preliminary information from EquiServe Trust Company, N.A. (the
"Depositary") and may be able to obtain such information from their broker.

THE BOARD OF DIRECTORS OF THE COMPANY HAS APPROVED THE ACQUISITION AGREEMENT
AND THE TRANSACTIONS CONTEMPLATED THEREBY BY A UNANIMOUS VOTE OF THOSE
DIRECTORS PRESENT AND VOTING, AND RECOMMENDS THAT STOCKHOLDERS ACCEPT THE
OFFER AND TENDER THEIR SHARES PURSUANT TO THE OFFER. CERTAIN OFFICERS OF THE
COMPANY HAVE AGREED TO TENDER A SUBSTANTIAL PORTION OF THEIR BENEFICIALLY
OWNED SHARES IN THE OFFER.




THE PURCHASER EXPRESSLY RESERVES THE RIGHT (BUT SHALL NOT BE OBLIGATED) TO
WAIVE ANY CONDITION TO THE OFFER, MODIFY THE TERMS OF THE OFFER OR INCREASE
THE OFFER PRICE, EXCEPT THAT, WITHOUT THE CONSENT OF THE COMPANY, THE
PURCHASER SHALL NOT (I) INCREASE OR REDUCE THE NUMBER OF SHARES SUBJECT TO
THE OFFER, (II) REDUCE THE PRICE PER SHARE TO BE PAID PURSUANT TO THE OFFER,
(III) MODIFY OR ADD TO THE CONDITIONS OF THE OFFER, (IV) CHANGE THE FORM OF
CONSIDERATION PAYABLE IN THE OFFER OR (V) OTHERWISE AMEND THE OFFER IN ANY
MANNER ADVERSE TO THE HOLDERS OF SHARES.

For purposes of the Offer, the Purchaser will be deemed to have accepted for
payment, and thereby purchased, Shares validly tendered to the Purchaser and
not withdrawn as, if and when the Purchaser gives oral or written notice to
the Depositary of the Purchaser's acceptance for payment of such Shares.
Payment for Shares accepted for payment pursuant to the Offer will be made by
deposit of the purchase price therefor with the Depositary, which will act as
agent for tendering stockholders for the purpose of receiving payment from
the Purchaser and transmitting payment to tendering stockholders whose shares
have been accepted for payment. In all cases, payment for Shares accepted for
payment pursuant to the Offer will be made only after timely receipt by the
Depositary of (a) certificates for such Shares ("Share Certificates"),
together with a Letter of Transmittal, properly completed and duly executed,
and any required signature guarantees, or, (b) in the case of a transfer
effected pursuant to the book-entry transfer procedures, a Book-Entry
Confirmation and either a Letter of Transmittal, properly completed and duly
executed, and any required signature guarantees, or an Agent's Message (as
defined in Section 2 of the Offer to Purchase), and any other required
documents. UNDER NO CIRCUMSTANCES WILL INTEREST BE PAID ON THE PURCHASE PRICE
FOR TENDERED SHARES, REGARDLESS OF ANY EXTENSION OF OR AMENDMENT TO THE OFFER
OR ANY DELAY IN PAYING FOR SUCH SHARES. The Purchaser will pay any stock
transfer taxes with respect to the transfer and sale of Shares to it or its
order pursuant to the Offer, except as otherwise provided in Instruction 6 of
the Letter of Transmittal, as well as any charges of the Depositary and
Innisfree M&A Incorporated (the "Information Agent").

The term "Expiration Date" means 12:00 midnight, New York City time, on
Friday, October 26, 2001, unless and until the Purchaser shall have extended
the period of time during which the Offer is open in accordance with the
terms of the Acquisition Agreement, in which event the term "Expiration Date"
shall mean the latest time and date on which the Offer, as so extended by the
Purchaser, will expire. The Purchaser will extend the Offer, and thereby
delay acceptance for payment of, and the payment for, any Shares, by giving
oral or written notice of such extension to the Depositary, if at the
Expiration Date any of the conditions to the Purchaser's obligation to
purchase Shares are not satisfied, until such time as such conditions are
satisfied or waived. Each such extension will be for a period of no more than
ten business days, and the Purchaser may not, without the consent of the
Company, extend the Offer beyond April 1, 2002 (provided that (1) if the
applicable waiting period under the HSR Act has not expired or been
terminated, or if the condition set forth in clause (a) of the first sentence
of Section 14 of the Offer to Purchase has not been satisfied



due to the existence of an antitrust-related injunction, then the Purchaser
or the Company may extend this date from time to time to a date no later than
September 30, 2002, (2) if the condition set forth in clause (a) of that
sentence has not been satisfied due to the existence of an injunction in
connection with a third party proposal to acquire more than 35% of the
Company, then this date will be extended to the earlier to occur of September
30, 2002 and any earlier date specified by the Company at any time prior to
September 30, 2002, and (3) if the condition set forth in clause (f) of that
sentence has not been satisfied, then the Purchaser or the Company may extend
this date from time to time to a date no later than September 30, 2002). The
Purchaser will also extend the Offer for any period required by any rule,
regulation, interpretation or position of the Securities and Exchange
Commission or the staff thereof applicable to the Offer or any period
required by applicable law. Any such extension will be followed by a public
announcement thereof no later than 9:00 a.m., New York City time, on the next
business day after the day on which the Offer was scheduled to expire. The
Purchaser will not make available a "subsequent offering period" (within the
meaning of Rule 14d-11 under the Securities Exchange Act of 1934, as amended
(the "Exchange Act")).

If the Purchaser is delayed in its acceptance for payment of or payment for
Shares or is unable to accept for payment or pay for Shares pursuant to the
Offer for any reason, then, without prejudice to the Purchaser's rights under
the Offer (but subject to compliance with Rule 14e-1(c) under the Exchange
Act (relating to a bidder's obligation to pay for or return tendered
securities promptly after the termination or withdrawal of such bidder's
offer) and the terms of the Acquisition Agreement (requiring that the
Purchaser pay for Shares accepted for payment as soon as practicable after
the Expiration Date)), the Depositary may, nevertheless, on behalf of the
Purchaser, retain tendered Shares, and such Shares may not be withdrawn
except to the extent tendering stockholders are entitled to do so as
described in Section 3 of the Offer to Purchase.

If any tendered Shares are not accepted for payment pursuant to the Offer
because of an invalid tender, proration or otherwise, the certificates for
such Shares will be returned (and, if certificates are submitted for more
Shares than are tendered, new certificates for the Shares not tendered will
be sent), in each case without expense to the tendering stockholder (or, in
the case of Shares delivered by book-entry transfer of such Shares into the
Depositary's account at the Book-Entry Transfer Facility pursuant to the
book-entry transfer procedures described in Section 2 of the Offer to
Purchase, such Shares will be credited to an account maintained at the
Book-Entry Transfer Facility), as promptly as practicable following the
expiration or termination of the Offer. Except as otherwise provided below,
tenders of Shares are irrevocable. Shares tendered pursuant to the Offer may
be withdrawn at any time prior to the Expiration Date and, unless accepted
for payment and paid for by the Purchaser pursuant to the Offer, may also be
withdrawn at any time after November 26, 2001 (or such later date as may
apply in case the Offer is extended). For a withdrawal to be effective, a
written or facsimile transmission notice of withdrawal must be timely
received by the Depositary at one of its addresses



set forth on the back cover of the Offer to Purchase. Any such notice of
withdrawal must specify the name of the person who tendered the Shares to be
withdrawn, the number of Shares to be withdrawn and the name of the
registered holder of the Shares to be withdrawn, if different from the name
of the person who tendered the Shares. If Share Certificates to be withdrawn
have been delivered or otherwise identified to the Depositary, then, prior to
the physical release of such certificates, the serial numbers shown on such
certificates must be submitted to the Depositary and, unless such Shares have
been tendered by an Eligible Institution (as defined in Section 2 of the
Offer to Purchase), any and all signatures on the notice of withdrawal must
be guaranteed by an Eligible Institution. If Shares have been tendered
pursuant to the procedures for book-entry transfer as set forth in Section 2
of the Offer to Purchase, any notice of withdrawal must also specify the name
and number of the account at the Book-Entry Transfer Facility to be credited
with the withdrawn Shares and otherwise comply with the Book-Entry Transfer
Facility's procedures.

Withdrawals of tenders of Shares may not be rescinded. Any Shares properly
withdrawn will be deemed not validly tendered for purposes of the Offer, but
may be retendered by again following one of the procedures described in
Section 2 of the Offer to Purchase at any time prior to the Expiration Date.
All questions as to the form and validity (including time of receipt) of
notices of withdrawal will be determined by the Purchaser in its sole
discretion, which determination will be final and binding.

The Offer to Purchase, the related Letter of Transmittal and other relevant
materials will be mailed by the Company to record holders of Shares, and will
be furnished to brokers, dealers, banks, trust companies and similar persons
whose names, or the names of whose nominees, appear on the Company's
stockholder lists, or, if applicable, who are listed as participants in a
clearing agency's security position listing, for subsequent transmittal to
beneficial owners of Shares.

The receipt of cash in the Offer will be a taxable transaction for U.S.
federal income tax purposes and may also be a taxable transaction under
applicable state, local or foreign income or other tax laws. Stockholders
should consult their own tax advisors about the particular effect the
proposed transactions will have on their Shares.

The information required to be disclosed by Rule 14d-6(d)(1) under the
Exchange Act is contained in the Offer to Purchase and is incorporated herein
by reference.

THE OFFER TO PURCHASE AND THE RELATED LETTER OF TRANSMITTAL CONTAIN IMPORTANT
INFORMATION WHICH SHOULD BE READ BEFORE ANY DECISION IS MADE WITH RESPECT TO
THE OFFER.

Questions and requests for assistance may be directed to the Information
Agent at the address and telephone number set forth below. Requests for
additional copies of the Offer to Purchase, the related Letter of Transmittal
may be directed to the Information Agent, or to brokers, dealers, banks or
trust companies. Such additional copies will be promptly furnished at the
Purchaser's expense. The Purchaser and Parent will not pay any fees or
commissions to any




broker or dealer or any other person (other than the Dealer Manager) for
soliciting tenders of Shares pursuant to the Offer.

The Information Agent for the Offer is:
InnisFree M&A Incorporated
501 Madison Avenue, 20th Floor
New York, New York 10022
Banks and Brokers Call Collect: (212) 750-5833
All Others Please Call Toll-Free: (888) 750-5834

The Dealer Manager for the Offer is:
Lehman Brothers
101 Hudson Street
Jersey City, NJ 07302
(646) 351-4463 or (646) 351-4494
September 28, 2001