EXHIBIT 23.6

               CONSENT OF ERNST & YOUNG LLP, INDEPENDENT AUDITORS

We consent to the reference to our firm under the caption "Experts" in the
Proxy Statement of Cell Pathways, Inc. that is made a part of Amendment No. 2
to the Registration Statement (Form S-4 No. 333-103644) and Prospectus of OSI
Pharmaceuticals, Inc. for the registration of 4,208,486 shares of its common
stock and up to 43,521,051 contingent value rights and to the incorporation by
reference therein of our report dated February 1, 2002, with respect to the
financial statements of the Oncology Related Assets, Liabilities and Activities
of Gilead Sciences, Inc. included in the Current Report on Form 8-K/A of OSI
Pharmaceuticals, Inc. filed with the Securities and Exchange Commission on
March 6, 2002.


                                                           /s/ ERNST & YOUNG LLP


Palo Alto, California
April 28, 2003