EXHIBIT 23.1

                          INDEPENDENT AUDITORS' CONSENT

The Board of Directors
Cell Pathways, Inc.

We consent to the incorporation by reference in the Registration Statements on
Form S-3 (No. 333-86624 and No. 333-57784) and the Registration Statements on
Form S-8 (No. 333-91118, No. 333-65072, No. 333-42274, No. 333-39509, No.
333-06861, No. 33-64713, No. 33-60182, No. 33-38443, and No. 33-8980) of OSI
Pharmaceuticals, Inc. and subsidiaries of our report dated February 14, 2003,
with respect to the consolidated balance sheet of Cell Pathways, Inc. and
subsidiaries as of December 31, 2002, and the related consolidated statements of
operations, stockholders' equity (deficit) and partners' investment, and cash
flows for the year then ended and for the period from August 10, 1990
(inception) through December 31, 2002, which report appears in the Form 8-K of
OSI Pharmaceuticals, Inc. dated June 27, 2003.

The consolidated financial statements of Cell Pathways, Inc. and subsidiaries as
of December 31, 2001 and for each of the years in the two-year period ended
December 31, 2001 and for the period from August 10, 1990 (inception) through
December 31, 2002, to the extent related to the period from August 10, 1990
(inception) through December 31, 2001, were audited by other auditors who have
ceased operations. Those auditors expressed an unqualified opinion on those
financial statements in their report dated February 25, 2002. Our opinion on the
consolidated statements of operations, stockholders' equity (deficit) and
partners' investment, and cash flows, insofar as it relates to the amounts
included for the period from August 10, 1990 (inception) through December 31,
2001, is based solely on the report of the other auditors.

Our report dated February 14, 2003, contains an explanatory paragraph that
states that Cell Pathways' recurring losses from operations, accumulated deficit
and limited liquid resources raise substantial doubt about Cell Pathways'
ability to continue as a going concern. Cell Pathways' consolidated financial
statements do not include any adjustments that might result from the outcome of
that uncertainty.

                                                          /s/ KPMG LLP

Philadelphia, Pennsylvania
June 27, 2003