OSI Pharmaceuticals Announces Three Additions to Its 2006 Board of Director Slate; David Niemiec, Skip Klein, Santo Costa are Nominated as New Directors

"The nomination of David, Skip and Sandy to the Company's Board ofDirectors exemplifies our commitment to continually strengthening andbroadening the expertise needed to provide the highest standards ofcorporate governance at the Board level," stated Robert A. Ingram,Chairman of the Board of Directors of OSI Pharmaceuticals. "Thesethree individuals bring particular expertise in the financial, legal,technical and corporate governance arenas as well as extensive WallStreet experience. They will add to the existing strength and combinedexperience of the OSI Board as we continue to provide oversight andsupport to the Company's goal of building a top-tier biotechnologycompany."

Sandy Costa, 60, is currently Of Counsel at the law firm MaupinTaylor, P.A. Mr. Costa previously held several positions withQuintiles Transnational Corp., including President and Chief OperatingOfficer and Vice-Chairman. Prior to joining Quintiles, Mr. Costa spent23 years in the pharmaceutical industry, most recently as Senior VicePresident, Administration and General Counsel of Glaxo Inc. where healso sat on the company's board of directors. In addition, Mr. Costasits on the board of directors of NPS Pharmaceuticals, CV TherapeuticsInc., DigiScripts, LaboPharm, Constella Group and is Chairman ofNeuroMedix. Mr. Costa is an adjunct professor in the clinical researchprogram at the Campbell University School of Pharmacy. He also sits onthe Board of the Duke Cancer Patient Support Program and the DukeUniversity Medical Center Board of Visitors. Mr. Costa received hisB.S. in pharmacy and his J.D. from St. John's University.

Skip Klein, 45, is currently Managing Director of Gauss CapitalAdvisors, LLC, a financial consulting and investment advisory firmfocused on biopharmaceutical companies, which he founded in March1998. In addition to his investment advisory and financial consultingactivities, Mr. Klein currently serves as a Venture Partner of RedAbbey Venture Partners, LP, a life sciences private equity fund. As anactive life sciences investor and industry analyst, Mr. Klein has over15 years of experience finding and analyzing life sciencesopportunities for mutual funds, investment banks and biopharmaceuticalcompanies. Mr. Klein serves on the board of directors of four publiclytraded biotechnology companies: Biomarin Pharmaceutical, Inc.;Clinical Data, Inc.; ISIS Pharmaceuticals, Inc. and NPSPharmaceuticals, Inc. Mr. Klein earned his B.A. in economics from YaleUniversity and his M.B.A. from the Stanford Graduate School ofBusiness.

David W. Niemiec, 56, is a private equity investor and an Advisorto Saratoga Partners, a middle market private equity firm. Mr. Niemiecwas formerly with the investment banking firm of Dillon, Read & Co.Inc., where he was Vice Chairman of the board of directors, a memberof the firm's four-person Management Committee, Chief AdministrativeOfficer and Chief Financial Officer. Mr. Niemiec has over 20 years ofprivate equity experience, in part through his involvement in DillonRead's direct investment program involving more than 100 portfoliocompanies. He is currently a member of the board of directors ofEmeritus Corporation, as well as a director and trustee of variousTempleton Funds, which are internationally oriented mutual funds ofthe Franklin Templeton Investments group. Mr. Niemiec received hisB.A. from Harvard College and his M.B.A. from Harvard Business School.

OSI also announced that its Board has adopted a retirement policyfor directors at age 72. In accordance with the new policy, Sir MarkRichmond, Ph.D., has advised the Company that, pending his re-electionfor the 2006-7 term, he will retire from his position as a Director atthe end of 2006 thereby facilitating an appropriate transition periodwith the new directors. The Board of Directors also announced itsintention to cap the number of directors serving on the Board at 12following Sir Mark Richmond's retirement.

About OSI Pharmaceuticals

OSI Pharmaceuticals is committed to "shaping medicines andchanging lives" by discovering, developing and commercializinghigh-quality and novel pharmaceutical products that extend life orimprove the quality of life for patients with cancer, eye diseases anddiabetes. The Company operates through three business teams, (OSI)Oncology, (OSI) Eyetech and (OSI) Prosidion. (OSI) Oncology is focusedon developing molecular targeted therapies designed to change theparadigm of cancer care. (OSI) Eyetech specializes in the developmentand commercialization of novel therapeutics to treat diseases of theeye. (OSI) Prosidion is committed to the generation of novel, targetedtherapies for the treatment of type 2 diabetes and obesity. OSI'sflagship product, Tarceva(R) (erlotinib), is the first drug discoveredand developed by OSI to obtain FDA approval and the only EGFRinhibitor to have demonstrated the ability to improve survival in bothnon-small cell lung cancer and pancreatic cancer patients. OSI marketsTarceva through partnerships with Genentech, Inc. in the United Statesand with Roche throughout the rest of the world. Macugen(R)(pegaptanib sodium injection) is approved in the United States andEurope for the treatment of neovascular age-related maculardegeneration. OSI commercializes Macugen in partnership with PfizerInc. For additional information about OSI, please visithttp://www.osip.com.

Where You Can Find Additional Information

OSI intends to file a Proxy Statement with the Securities andExchange Commission (SEC) in connection with OSI's Annual Meeting ofStockholders to be held on June 14, 2006. The Proxy Statement will bemailed to the stockholders of OSI to consider and vote upon mattersincluding the election of directors. Investors and stockholders areurged to carefully read the Proxy Statement filed with the SEC when itbecomes available because it will contain important information.Investors and stockholders may obtain free copies of this document(when it is available) and other documents filed with the SEC at theSEC's web site at www.sec.gov. These documents can also be obtainedfor free from OSI by directing a request to OSI Investor Relations at631-962-2000.

This news release contains forward-looking statements. Thesestatements are subject to known and unknown risks and uncertaintiesthat may cause actual future experience and results to differmaterially from the statements made. Factors that might cause such adifference include, among others, the completion of clinical trials,the FDA review process and other governmental regulation, OSI's andits collaborators' abilities to successfully develop and commercializedrug candidates, competition from other pharmaceutical companies, theability to effectively market products, and other factors described inOSI Pharmaceuticals' filings with the Securities and ExchangeCommission.