<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM ONYX
PHARMACEUTICALS, INC.'S UNAUDITED CONDENSED BALANCE SHEET DATED MARCH 31, 2000,
AND UNAUDITED CONDENSED STATEMENT OF OPERATIONS FOR THE THREE MONTHS ENDED MARCH
31, 2000, AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL
STATEMENTS.
</LEGEND>
<MULTIPLIER> 1,000

                             
<PERIOD-TYPE>                   3-MOS
<FISCAL-YEAR-END>                          DEC-31-2000
<PERIOD-START>                             JAN-01-2000
<PERIOD-END>                               MAR-31-2000
<CASH>                                          32,918
<SECURITIES>                                     4,239
<RECEIVABLES>                                    2,135
<ALLOWANCES>                                         0
<INVENTORY>                                          0
<CURRENT-ASSETS>                                39,810
<PP&E>                                          12,512
<DEPRECIATION>                                   9,575
<TOTAL-ASSETS>                                  43,136
<CURRENT-LIABILITIES>                            9,602
<BONDS>                                          1,832
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                            14
<OTHER-SE>                                      31,687
<TOTAL-LIABILITY-AND-EQUITY>                    43,136
<SALES>                                              0
<TOTAL-REVENUES>                                 5,837
<CGS>                                                0
<TOTAL-COSTS>                                    7,912
<OTHER-EXPENSES>                                     0
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                                  51
<INCOME-PRETAX>                                (1,680)
<INCOME-TAX>                                         0
<INCOME-CONTINUING>                            (1,680)
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                   (1,680)
<EPS-BASIC>                                     (0.12)
<EPS-DILUTED>                                   (0.12)