<TABLE> <S> <C>

<ARTICLE> 6
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE JOHN
HANCOCK VARIABLE SERIES TRUST I ANNUAL REPORT DATED DECEMBER 31, 1998 AND IS
QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
<SERIES>
   <NUMBER> 14
   <NAME> MID CAP VALUE
<MULTIPLIER> 1000
       
<S>                             <C>
<PERIOD-TYPE>                   YEAR
<FISCAL-YEAR-END>                          DEC-31-1998
<PERIOD-START>                             JAN-01-1998
<PERIOD-END>                               DEC-31-1998
<INVESTMENTS-AT-COST>                           94,039
<INVESTMENTS-AT-VALUE>                          95,152
<RECEIVABLES>                                      367
<ASSETS-OTHER>                                       0
<OTHER-ITEMS-ASSETS>                                 0
<TOTAL-ASSETS>                                  95,519
<PAYABLE-FOR-SECURITIES>                           688
<SENIOR-LONG-TERM-DEBT>                              0
<OTHER-ITEMS-LIABILITIES>                           11
<TOTAL-LIABILITIES>                                699
<SENIOR-EQUITY>                                      0
<PAID-IN-CAPITAL-COMMON>                       104,944
<SHARES-COMMON-STOCK>                            7,781
<SHARES-COMMON-PRIOR>                                0
<ACCUMULATED-NII-CURRENT>                            0
<OVERDISTRIBUTION-NII>                               0
<ACCUMULATED-NET-GAINS>                        (9,170)
<OVERDISTRIBUTION-GAINS>                             0
<ACCUM-APPREC-OR-DEPREC>                         (954)
<NET-ASSETS>                                    94,820
<DIVIDEND-INCOME>                                1,368
<INTEREST-INCOME>                                  303
<OTHER-INCOME>                                       0
<EXPENSES-NET>                                     851
<NET-INVESTMENT-INCOME>                            820
<REALIZED-GAINS-CURRENT>                       (8,690)
<APPREC-INCREASE-CURRENT>                      (4,194)
<NET-CHANGE-FROM-OPS>                         (12,064)
<EQUALIZATION>                                       0
<DISTRIBUTIONS-OF-INCOME>                        (820)
<DISTRIBUTIONS-OF-GAINS>                             0
<DISTRIBUTIONS-OTHER>                                0
<NUMBER-OF-SHARES-SOLD>                          4,722
<NUMBER-OF-SHARES-REDEEMED>                    (1,693)
<SHARES-REINVESTED>                                 66
<NET-CHANGE-IN-ASSETS>                          29,847
<ACCUMULATED-NII-PRIOR>                              0
<ACCUMULATED-GAINS-PRIOR>                            0
<OVERDISTRIB-NII-PRIOR>                              0
<OVERDIST-NET-GAINS-PRIOR>                           0
<GROSS-ADVISORY-FEES>                              709
<INTEREST-EXPENSE>                                   0
<GROSS-EXPENSE>                                    851
<AVERAGE-NET-ASSETS>                            88,520
<PER-SHARE-NAV-BEGIN>                            13.87
<PER-SHARE-NII>                                   0.11
<PER-SHARE-GAIN-APPREC>                         (1.68)
<PER-SHARE-DIVIDEND>                            (0.11)
<PER-SHARE-DISTRIBUTIONS>                            0
<RETURNS-OF-CAPITAL>                                 0
<PER-SHARE-NAV-END>                              12.19
<EXPENSE-RATIO>                                   0.96
<AVG-DEBT-OUTSTANDING>                               0
<AVG-DEBT-PER-SHARE>                                 0
        

</TABLE>