WARNING: THE EDGAR SYSTEM ENCOUNTERED ERROR(S) WHILE PROCESSING THIS SCHEDULE.

  

<ARTICLE>                          5
<CIK>                              0001010915
<NAME>                             MICROCIDE PHARMACEUTICALS, INC.
<MULTIPLIER>                       1,000
<CURRENCY>                         U.S. DOLLARS

                                
<PERIOD-TYPE>                      QTR-3
<FISCAL-YEAR-END>                  DEC-31-1999
<PERIOD-START>                     JUL-1-1999
<PERIOD-END>                       SEP-30-1999

<EXCHANGE-RATE>                    1
<CASH>                             8,483
<SECURITIES>                       15,181
<RECEIVABLES>                      754
<ALLOWANCES>                       0
<INVENTORY>                        0
<CURRENT-ASSETS>                   25,389
<PP&E>                             19,843
<DEPRECIATION>                     (11,665)
<TOTAL-ASSETS>                     34,479
<CURRENT-LIABILITIES>              3,600
<BONDS>                            0
<PREFERRED-MANDATORY>              0
<PREFERRED>                        0
<COMMON>                           67,003
<OTHER-SE>                         (38,287)
<TOTAL-LIABILITY-AND-EQUITY>       34,479
<SALES>                            0
<TOTAL-REVENUES>                   1,592
<CGS>                              0
<TOTAL-COSTS>                      5,147
<OTHER-EXPENSES>                   0
<LOSS-PROVISION>                   0
<INTEREST-EXPENSE>                 82
<INCOME-PRETAX>                    (3,294)
<INCOME-TAX>                       0
<INCOME-CONTINUING>                (3,294)
<DISCONTINUED>                     0
<EXTRAORDINARY>                    0
<CHANGES>                          0
<NET-INCOME>                       (3,294)
<EPS-BASIC>                        (0.30)
<EPS-DILUTED>                      (0.30)