Exhibit 99.1

ARIAD Announces $10 Million Direct Equity Placement

    CAMBRIDGE, Mass.--(BUSINESS WIRE)--May 19, 2003--ARIAD
Pharmaceuticals, Inc. (Nasdaq: ARIA) today announced that it has
entered into definitive agreements with two institutional investors
for the purchase of 4 million shares of its common stock at $2.50 per
share in a direct equity placement for gross proceeds of $10 million.
The investors are The Riverview Group, LLC, the private equity
investment arm of Millennium Partners, LP, and Merlin Biomed Group.
The share price represents the average closing price of the Company's
common stock for the past ten trading days. The offering is expected
to close within two business days.
    Rodman & Renshaw, Inc. served as placement agent for the offering.
The shares were offered through prospectus supplements pursuant to the
Company's effective shelf registration statements.
    This press release shall not constitute an offer to sell or the
solicitation of an offer to buy, nor shall there be any sale of these
securities in any state in which such offer, solicitation or sale
would be unlawful prior to registration or qualification under the
securities laws of any such state.

    Some of the matters discussed herein are "forward-looking
statements" within the meaning of the Private Securities Litigation
Reform Act of 1995. Such statements are identified by the use of words
such as "anticipate," "estimate," "expect," "project," "intend,"
"plan," "believe," and other words and terms of similar meaning in
connection with any discussion of future operating or financial
performance. Such statements are based on management's current
expectations and are subject to certain factors, risks and
uncertainties that may cause actual results, outcome of events, timing
and performance to differ materially from those expressed or implied
by such forward-looking statements. These risks include, but are not
limited to, risks and uncertainties regarding the Company's ability to
conduct preclinical and clinical studies of its product candidates and
the results of such studies, regulatory oversight, intellectual
property claims, the timing, scope, cost and outcome of legal
proceedings, future capital needs, key employees, dependence on the
Company's collaborators and manufacturers, markets, economic
conditions, products, services, prices, reimbursement rates,
competition and other risks detailed in the Company's public filings
with the Securities and Exchange Commission, including ARIAD's Annual
Report on Form 10-K for the fiscal year ended December 31, 2002. The
information contained in this document is believed to be current as of
the date of original issue. The Company does not intend to update any
of the forward-looking statements after the date of this document to
conform these statements to actual results or to changes in the
Company's expectations, except as required by law.

    CONTACT: ARIAD Pharmaceuticals, Inc.
             Tom Pearson, 610/407-9260
             or
             Kathy Lawton, 617/621-2345