<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM CHIRON
CORPORATION UNAUDITED CONDENSED COLSOLIDATED BALANCE SHEET DATED JUNE 30, 1999
AND UNAUDITED CONDENSED CONSOLIDATED STATEMENT OF OPERATIONS FOR THE SIX MONTHS
ENDED JUNE 30, 1999 AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH
FINANCIAL STATEMENTS.
</LEGEND>
<MULTIPLIER> 1,000

                             
<PERIOD-TYPE>                   6-MOS
<FISCAL-YEAR-END>                          DEC-31-1999<F5>
<PERIOD-START>                             JAN-01-1999
<PERIOD-END>                               JUN-30-1999<F5>
<CASH>                                          47,534
<SECURITIES>                                 1,431,992<F1>
<RECEIVABLES>                                  179,286
<ALLOWANCES>                                         0
<INVENTORY>                                     93,233
<CURRENT-ASSETS>                             1,137,303
<PP&E>                                         538,129
<DEPRECIATION>                                 218,438
<TOTAL-ASSETS>                               2,400,600
<CURRENT-LIABILITIES>                          380,947
<BONDS>                                        349,145<F2>
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                         1,815
<OTHER-SE>                                   1,606,813<F3>
<TOTAL-LIABILITY-AND-EQUITY>                 2,400,600
<SALES>                                        194,289
<TOTAL-REVENUES>                               364,670
<CGS>                                           84,635
<TOTAL-COSTS>                                   84,635
<OTHER-EXPENSES>                               149,304<F4>
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                              11,708
<INCOME-PRETAX>                                 75,584
<INCOME-TAX>                                    18,112
<INCOME-CONTINUING>                             57,472
<DISCONTINUED>                                   3,009
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                    60,481
<EPS-BASIC>                                       0.33
<EPS-DILUTED>                                     0.33
<FN>
<F1>CONSISTS OF BOTH SHORT-TERM AND NONCURRENT INVESTMENTS IN MARKETABLE DEBT
SECURITIES.
<F2>CONSISTS OF CONVERTIBLE SUBORDINATED DEBENTURES AND NOTES PAYABLE, NET OF
CURRENT MATURITIES.
<F3>CONSISTS OF ADDITIONAL PAID-IN CAPITAL, ACCUMULATED DEFICIT, COST OF TREASURY
STOCK, AND ACCUMULATED OTHER COMPREHENSIVE LOSS.
<F4>CONSISTS OF RESEARCH AND DEVELOPMENT, RESTRUCTURING AND REORGANIZATION CHARGES
AND OTHER OPERATING EXPENSES.
<F5>DURING THE FIRST QUARTER OF 1999, THE COMPANY CHANGED ITS FISCAL YEAR FROM A 52
OR 53-WEEK YEAR ENDING ON THE SUNDAY NEAREST THE LAST DAY IN DECEMBER, TO A
CALENDAR YEAR ENDING ON DECEMBER 31.
</FN>