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                                                                      EXHIBIT 23

                          INDEPENDENT AUDITORS' CONSENT

The Board of Directors
OSI Pharmaceuticals, Inc.

We consent to incorporation by reference in the registration statements on Forms
S-3 (No. 333-12593 and No. 333-2451) and on Forms S-8 (No. 333-39509, No.
333-06861, No. 33-64713, No. 33-60182, No. 33-38443, and No. 33-8980) of OSI
Pharmaceuticals, Inc. of our report dated December 22, 1999, relating to the
consolidated balance sheets of OSI Pharmaceuticals, Inc. and subsidiaries as of
September 30, 1999 and 1998, and the related consolidated statements of
operations, stockholders' equity and cash flows for each of the years in the
three-year period ended September 30, 1999, which report appears in the
September 30, 1999 annual report on Form 10-K of OSI Pharmaceuticals, Inc.

                                                        /s/  KPMG LLP

Melville, New York
December 22, 1999