<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> 08
   <NAME> DIVERSIFIED MID CAP GROWTH
<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>                          166,644
<INVESTMENTS-AT-VALUE>                         194,444
<RECEIVABLES>                                      771
<ASSETS-OTHER>                                       1
<OTHER-ITEMS-ASSETS>                                 0
<TOTAL-ASSETS>                                 195,216
<PAYABLE-FOR-SECURITIES>                         1,752
<SENIOR-LONG-TERM-DEBT>                              0
<OTHER-ITEMS-LIABILITIES>                          132
<TOTAL-LIABILITIES>                              1,884
<SENIOR-EQUITY>                                      0
<PAID-IN-CAPITAL-COMMON>                       170,700
<SHARES-COMMON-STOCK>                           12,129
<SHARES-COMMON-PRIOR>                                0
<ACCUMULATED-NII-CURRENT>                            0
<OVERDISTRIBUTION-NII>                               0
<ACCUMULATED-NET-GAINS>                          (290)
<OVERDISTRIBUTION-GAINS>                             0
<ACCUM-APPREC-OR-DEPREC>                        22,922
<NET-ASSETS>                                   193,332
<DIVIDEND-INCOME>                                1,150
<INTEREST-INCOME>                                  393
<OTHER-INCOME>                                       0
<EXPENSES-NET>                                   1,760
<NET-INVESTMENT-INCOME>                          (217)
<REALIZED-GAINS-CURRENT>                         2,111
<APPREC-INCREASE-CURRENT>                        8,644
<NET-CHANGE-FROM-OPS>                           10,538
<EQUALIZATION>                                       0
<DISTRIBUTIONS-OF-INCOME>                            0
<DISTRIBUTIONS-OF-GAINS>                       (3,671)
<DISTRIBUTIONS-OTHER>                                0
<NUMBER-OF-SHARES-SOLD>                          1,216
<NUMBER-OF-SHARES-REDEEMED>                    (3,201)
<SHARES-REINVESTED>                                230
<NET-CHANGE-IN-ASSETS>                        (20,280)
<ACCUMULATED-NII-PRIOR>                              0
<ACCUMULATED-GAINS-PRIOR>                            0
<OVERDISTRIB-NII-PRIOR>                              0
<OVERDIST-NET-GAINS-PRIOR>                           0
<GROSS-ADVISORY-FEES>                            1,490
<INTEREST-EXPENSE>                                   0
<GROSS-EXPENSE>                                  1,760
<AVERAGE-NET-ASSETS>                           198,741
<PER-SHARE-NAV-BEGIN>                            15.39
<PER-SHARE-NII>                                 (0.02)
<PER-SHARE-GAIN-APPREC>                           0.88
<PER-SHARE-DIVIDEND>                                 0
<PER-SHARE-DISTRIBUTIONS>                       (0.31)
<RETURNS-OF-CAPITAL>                                 0
<PER-SHARE-NAV-END>                              15.94
<EXPENSE-RATIO>                                   0.89
<AVG-DEBT-OUTSTANDING>                               0
<AVG-DEBT-PER-SHARE>                                 0
        

</TABLE>