<TABLE> <S> <C>

<ARTICLE> 6
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATIN 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> 14
   <NAME> MID CAP VALUE
<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>                           93,777
<INVESTMENTS-AT-VALUE>                         100,306
<RECEIVABLES>                                      418
<ASSETS-OTHER>                                       0
<OTHER-ITEMS-ASSETS>                                 0
<TOTAL-ASSETS>                                 100,724
<PAYABLE-FOR-SECURITIES>                           512
<SENIOR-LONG-TERM-DEBT>                              0
<OTHER-ITEMS-LIABILITIES>                           13
<TOTAL-LIABILITIES>                                525
<SENIOR-EQUITY>                                      0
<PAID-IN-CAPITAL-COMMON>                        91,973
<SHARES-COMMON-STOCK>                            7,437
<SHARES-COMMON-PRIOR>                                0
<ACCUMULATED-NII-CURRENT>                            0
<OVERDISTRIBUTION-NII>                               0
<ACCUMULATED-NET-GAINS>                          2,249
<OVERDISTRIBUTION-GAINS>                             0
<ACCUM-APPREC-OR-DEPREC>                         5,977
<NET-ASSETS>                                   100,199
<DIVIDEND-INCOME>                                  748
<INTEREST-INCOME>                                   50
<OTHER-INCOME>                                       0
<EXPENSES-NET>                                     432
<NET-INVESTMENT-INCOME>                            366
<REALIZED-GAINS-CURRENT>                         2,249
<APPREC-INCREASE-CURRENT>                        6,931
<NET-CHANGE-FROM-OPS>                            9,546
<EQUALIZATION>                                       0
<DISTRIBUTIONS-OF-INCOME>                        (366)
<DISTRIBUTIONS-OF-GAINS>                             0
<DISTRIBUTIONS-OTHER>                                0
<NUMBER-OF-SHARES-SOLD>                          1,297
<NUMBER-OF-SHARES-REDEEMED>                    (1,671)
<SHARES-REINVESTED>                                 30
<NET-CHANGE-IN-ASSETS>                           5,379
<ACCUMULATED-NII-PRIOR>                              0
<ACCUMULATED-GAINS-PRIOR>                            0
<OVERDISTRIB-NII-PRIOR>                              0
<OVERDIST-NET-GAINS-PRIOR>                           0
<GROSS-ADVISORY-FEES>                              368
<INTEREST-EXPENSE>                                   0
<GROSS-EXPENSE>                                    432
<AVERAGE-NET-ASSETS>                                 0
<PER-SHARE-NAV-BEGIN>                            12.19
<PER-SHARE-NII>                                    .05
<PER-SHARE-GAIN-APPREC>                           1.28
<PER-SHARE-DIVIDEND>                               .05
<PER-SHARE-DISTRIBUTIONS>                            0
<RETURNS-OF-CAPITAL>                                 0
<PER-SHARE-NAV-END>                              13.47
<EXPENSE-RATIO>                                    .93


</TABLE>