<TABLE> <S> <C>

<PAGE>
<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM CHIRON
CORPORATION'S CONSOLIDATED BALANCE SHEET DATED DECEMBER 31, 1996 AND
CONSOLIDATED STATEMENT OF OPERATIONS FOR THE YEAR ENDED DECEMBER 31, 1996 AND IS
QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
<RESTATED>
<MULTIPLIER> 1,000

<S>                             <C>
<PERIOD-TYPE>                   YEAR
<FISCAL-YEAR-END>                          DEC-31-1996<F5>
<PERIOD-START>                             JAN-01-1996
<PERIOD-END>                               DEC-31-1996<F5>
<CASH>                                          68,114
<SECURITIES>                                    60,721<F1>
<RECEIVABLES>                                  372,663
<ALLOWANCES>                                    20,692
<INVENTORY>                                    180,534
<CURRENT-ASSETS>                               696,768
<PP&E>                                         796,821
<DEPRECIATION>                                 213,217
<TOTAL-ASSETS>                               1,688,670
<CURRENT-LIABILITIES>                          473,169
<BONDS>                                        419,589<F2>
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                         1,707
<OTHER-SE>                                     763,148<F3>
<TOTAL-LIABILITY-AND-EQUITY>                 1,688,670
<SALES>                                        804,909
<TOTAL-REVENUES>                             1,101,840
<CGS>                                          342,031
<TOTAL-COSTS>                                  342,031
<OTHER-EXPENSES>                               358,882<F4>
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                              30,934
<INCOME-PRETAX>                                 78,745
<INCOME-TAX>                                    22,142
<INCOME-CONTINUING>                             56,603
<DISCONTINUED>                                 (1,458)<F7>
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                    55,145
<EPS-PRIMARY>                                     0.33<F6>
<EPS-DILUTED>                                     0.31<F6>
<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>ACTUAL FISCAL YEAR END WAS DEC-29-1996.  FOR PRESENTATION PURPOSES, DATES USED
IN THE CONSOLIDATED FINANCIAL STATEMENTS AND NOTES REFER TO THE FISCAL MONTH END.
<F6>REPRESENTS NET INCOME PER SHARE.
<F7>ON DECEMBER 29, 1997, CHIRON CORPORATION COMPLETED THE SALE OF ITS OPHTHALMIC
BUSINESS UNIT, CHIRON VISION CORPORATION.  THIS SCHEDULE HAS BEEN RESTATED TO
REFLECT THE RESULTS OF CHIRON VISION CORPORATION AS DISCONTINUED OPERATIONS.
</FN>


</TABLE>