<TABLE> <S> <C>

<PAGE>
<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM CHIRON
CORPORATION'S UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEET DATED MARCH 31,
1998 AND UNAUDITED CONDENSED CONSOLIDATED STATEMENT OF OPERATIONS FOR THE
THREE MONTHS ENDED MARCH 31, 1998 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-31-1998<F5>
<PERIOD-START>                             JAN-01-1998
<PERIOD-END>                               MAR-31-1998<F5>
<CASH>                                         177,590
<SECURITIES>                                   270,727<F1>
<RECEIVABLES>                                  295,532
<ALLOWANCES>                                         0
<INVENTORY>                                    133,224
<CURRENT-ASSETS>                               863,843
<PP&E>                                         724,254
<DEPRECIATION>                                 256,123
<TOTAL-ASSETS>                               1,755,401
<CURRENT-LIABILITIES>                          366,121
<BONDS>                                        400,072<F2>
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                         1,771
<OTHER-SE>                                     964,056<F3>
<TOTAL-LIABILITY-AND-EQUITY>                 1,755,401
<SALES>                                        204,472
<TOTAL-REVENUES>                               268,905
<CGS>                                           88,981
<TOTAL-COSTS>                                   88,981
<OTHER-EXPENSES>                               115,676<F4>
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                               7,046
<INCOME-PRETAX>                                (8,041)
<INCOME-TAX>                                     2,810
<INCOME-CONTINUING>                           (10,851)
<DISCONTINUED>                                  65,332
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                    54,481
<EPS-PRIMARY>                                     0.31<F6>
<EPS-DILUTED>                                     0.31<F7>
<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, ACCUMULATED
OTHER COMPREHENSIVE LOSS AND NOTES RECEIVABLE FROM STOCK SALES.
<F4>CONSISTS OF RESEARCH AND DEVELOPMENT, RESTRUCTURING AND REORGANIZATION
CHARGES AND OTHER OPERATING EXPENSES.
<F5>ACTUAL FISCAL YEAR END WILL BE, AND PERIOD END WAS, JAN-03-1999 AND 
MAR-29-1998, RESPECTIVELY. FOR PRESENTATION PURPOSES, DATES USED IN THE 
CONSOLIDATED FINANCIAL STATEMENTS AND NOTES REFER TO THE FISCAL MONTH END.
<F6>REPRESENTS BASIC NET INCOME PER SHARE. BASIC LOSS PER SHARE FROM CONTINUING
OPERATIONS AND BASIC INCOME PER SHARE FROM DISCONTINUED OPERATIONS WERE ($0.06)
AND $0.37, RESPECTIVELY.
<F7>REPRESENTS DILUTED NET INCOME PER SHARE. DILUTED LOSS PER SHARE FROM
CONTINUING OPERATIONS AND DILUTED INCOME PER SHARE FROM DISCONTINUED OPERATIONS 
WERE ($0.06) AND $0.37, RESPECTIVELY.
</FN>
        

</TABLE>