Exhibit 99.1

 ARIAD Raises $54 Million Through Completion of Common Stock Offering

    CAMBRIDGE, Mass.--(BUSINESS WIRE)--Aug. 11, 2005--ARIAD
Pharmaceuticals, Inc. (Nasdaq: ARIA) today announced the completion of
its previously announced underwritten public offering of 7,500,000
shares of its common stock. The shares were priced at $7.20 per share
resulting in gross proceeds to ARIAD of $54 million.
    Lehman Brothers Inc. acted as sole book-running manager in this
offering. Lazard Capital Markets LLC and SG Cowen & Co., LLC acted as
co-managers.

    This press release does not constitute an offer to sell or the
solicitation of an offer to buy any of the securities, nor shall there
be any sale of the 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. A
prospectus supplement relating to these securities has been filed with
the Securities and Exchange Commission. This offering of the shares of
common stock was made only by means of the prospectus supplement and
related prospectus, a copy of which is available from Lehman Brothers,
Inc., Prospectus Department, c/o ADP Financial Services, Integrated
Distribution Services, 1155 Long Island Avenue, Edgewood, New York
11717, monica_castillo@adp.com or at the Securities and Exchange
Commission's website at www.sec.gov.

    ARIAD is engaged in the discovery and development of breakthrough
medicines to treat cancer by regulating cell signaling with small
molecules.


    CONTACT: ARIAD Pharmaceuticals, Inc.
             Edward Fitzgerald (Investors)
             617-621-2345
             or
             Andrea Johnston (Media)
             Pure Communications
             910-681-1088