<TABLE> <S> <C>

<ARTICLE> 6
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE JOHN
HANCOCK VARIABLE SERIES TRUST I SEMIANNUAL REPORT DATED JUNE 30, 1999 AND IS
QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
<SERIES>
   <NUMBER> 22
   <NAME> SMALL/MID CAP CORE
<MULTIPLIER> 1000

<S>                             <C>
<PERIOD-TYPE>                   6-MOS
<FISCAL-YEAR-END>                          DEC-31-1999
<PERIOD-START>                             JAN-01-1999
<PERIOD-END>                               JUN-30-1999
<INVESTMENTS-AT-COST>                            5,339
<INVESTMENTS-AT-VALUE>                           6,275
<RECEIVABLES>                                        8
<ASSETS-OTHER>                                      50
<OTHER-ITEMS-ASSETS>                                 0
<TOTAL-ASSETS>                                   6,333
<PAYABLE-FOR-SECURITIES>                             0
<SENIOR-LONG-TERM-DEBT>                              0
<OTHER-ITEMS-LIABILITIES>                            1
<TOTAL-LIABILITIES>                                  1
<SENIOR-EQUITY>                                      0
<PAID-IN-CAPITAL-COMMON>                         5,570
<SHARES-COMMON-STOCK>                              645
<SHARES-COMMON-PRIOR>                                0
<ACCUMULATED-NII-CURRENT>                            6
<OVERDISTRIBUTION-NII>                               0
<ACCUMULATED-NET-GAINS>                             12
<OVERDISTRIBUTION-GAINS>                             0
<ACCUM-APPREC-OR-DEPREC>                           744
<NET-ASSETS>                                     6,332
<DIVIDEND-INCOME>                                   31
<INTEREST-INCOME>                                    1
<OTHER-INCOME>                                       0
<EXPENSES-NET>                                      26
<NET-INVESTMENT-INCOME>                              6
<REALIZED-GAINS-CURRENT>                            12
<APPREC-INCREASE-CURRENT>                          480
<NET-CHANGE-FROM-OPS>                              498
<EQUALIZATION>                                       0
<DISTRIBUTIONS-OF-INCOME>                          (6)
<DISTRIBUTIONS-OF-GAINS>                             0
<DISTRIBUTIONS-OTHER>                                0
<NUMBER-OF-SHARES-SOLD>                            174
<NUMBER-OF-SHARES-REDEEMED>                       (85)
<SHARES-REINVESTED>                                  0
<NET-CHANGE-IN-ASSETS>                           1,317
<ACCUMULATED-NII-PRIOR>                              0
<ACCUMULATED-GAINS-PRIOR>                            0
<OVERDISTRIB-NII-PRIOR>                              0
<OVERDIST-NET-GAINS-PRIOR>                           0
<GROSS-ADVISORY-FEES>                               21
<INTEREST-EXPENSE>                                   0
<GROSS-EXPENSE>                                     75
<AVERAGE-NET-ASSETS>                                 0
<PER-SHARE-NAV-BEGIN>                             9.02
<PER-SHARE-NII>                                    .01
<PER-SHARE-GAIN-APPREC>                            .78
<PER-SHARE-DIVIDEND>                                 0
<PER-SHARE-DISTRIBUTIONS>                            0
<RETURNS-OF-CAPITAL>                                 0
<PER-SHARE-NAV-END>                               9.81
<EXPENSE-RATIO>                                    .99


</TABLE>