OSI Pharmaceuticals to Webcast its R&D Analyst Day on Thursday, December 3rd

OSI Pharmaceuticals, Inc. (NASDAQ: OSIP) announced today that it will host a live webcast of its R&D Analyst Day on Thursday, December 3, 2009 at 12:30 p.m. Eastern Time. The webcast will be hosted by Colin Goddard, Ph.D., Chief Executive Officer, and members of OSI’s management team. The Company will discuss the status of its oncology and diabetes/obesity research and development programs, including its Tarceva^® (erlotinib) program, and will also provide a brief financial overview. The webcast is expected to last approximately three hours.

To access the webcast live via the Internet, please log on to www.osip.com approximately 15 minutes before the start of the event to allow for any software downloads that may be necessary. Following the webcast, an archive will be available at the same address until approximately December 31, 2010.

About OSI Pharmaceuticals

OSI Pharmaceuticals is committed to "shaping medicine and changing lives" by discovering, developing and commercializing high-quality, novel and differentiated targeted medicines designed to extend life and improve the quality of life for patients with cancer and diabetes/obesity. For additional information about OSI, please visit http://www.osip.com.

This news release contains forward-looking statements. These statements are subject to known and unknown risks and uncertainties that may cause actual future experience and results to differ materially from the statements made. Factors that might cause such a difference include, among others, OSI's and its collaborators' abilities to effectively market and sell Tarceva and to expand the approved indications for Tarceva, OSI’s ability to protect its intellectual property rights, safety concerns regarding Tarceva, competition to Tarceva and OSI’s drug candidates from other biotechnology and pharmaceutical companies, the completion of clinical trials, the effects of FDA and other governmental regulation, including pricing controls, OSI's ability to successfully develop and commercialize drug candidates, and other factors described in OSI Pharmaceuticals' filings with the Securities and Exchange Commission.