<TABLE> <S> <C>

<PAGE>
<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM CHIRON
CORPORATION'S CONSOLIDATED BALANCE SHEET DATED MARCH 31, 1997 AND
CONSOLIDATED STATEMENT OF OPERATIONS FOR THE THREE MONTHS ENDED MARCH 31,
1997 AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL
STATEMENTS.
</LEGEND>
<MULTIPLIER> 1,000
       
<S>                             <C>
<PERIOD-TYPE>                   3-MOS
<FISCAL-YEAR-END>                          DEC-31-1997<F6>
<PERIOD-START>                             JAN-01-1997
<PERIOD-END>                               MAR-31-1997<F6>
<CASH>                                          99,335
<SECURITIES>                                    41,945<F1>
<RECEIVABLES>                                  327,306
<ALLOWANCES>                                         0
<INVENTORY>                                    181,286
<CURRENT-ASSETS>                               699,319
<PP&E>                                         809,681
<DEPRECIATION>                                 227,795
<TOTAL-ASSETS>                               1,678,415
<CURRENT-LIABILITIES>                          467,573
<BONDS>                                        391,688<F2>
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                         1,724
<OTHER-SE>                                     788,010<F3>
<TOTAL-LIABILITY-AND-EQUITY>                 1,678,415
<SALES>                                        251,129
<TOTAL-REVENUES>                               330,283
<CGS>                                          108,332
<TOTAL-COSTS>                                  108,332
<OTHER-EXPENSES>                                94,984<F4>
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                               8,486
<INCOME-PRETAX>                                 22,228
<INCOME-TAX>                                     6,892
<INCOME-CONTINUING>                             15,336
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                    15,336
<EPS-PRIMARY>                                     0.09<F5>
<EPS-DILUTED>                                     0.09<F5>
<FN>
<F1>CONSISTS OF BOTH SHORT-TERM AND NONCURRENT INVESTMENTS IN MARKETABLE DEBT
SECURITIES.
<F2>CONSISTS OF CONVERTIBLE SUBORDINATED DEBENTURES, CAPITAL LEASE OBLIGATIONS,
AND NOTES PAYABLE, NET OF CURRENT MATURITIES.
<F3>CONSISTS OF ADDITIONAL PAID-IN CAPITAL, ACCUMULATED DEFICIT, CUMULATIVE
FOREIGN CURRENCY TRANSLATION ADJUSTMENT, UNREALIZED GAIN FROM INVESTMENTS
AND NOTES RECEIVABLE FROM STOCK SALES.
<F4>CONSISTS OF RESEARCH AND DEVELOPMENT AND OTHER OPERATING EXPENSES.
<F5>THE COMPANY DECLARED A 4-FOR-1 STOCK SPLIT EFFECTIVE AUG-02-1996.  PRIOR
FINANCIAL DATA SCHEDULES HAVE NOT BEEN RESTATED FOR THIS RECAPITALIZATION.
<F6>ACTUAL FISCAL YEAR END WILL BE, AND PERIOD END WAS, DEC-28-1997 AND
MAR-30-1997, RESPECTIVELY. FOR PRESENTATION PURPOSES, DATES USED IN THE
CONSOLIDATED FINANCIAL STATEMENTS AND NOTES REFER TO THE CALENDAR MONTH
END.
</FN>
        

</TABLE>