<TABLE> <S> <C>

<ARTICLE> 6
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM JOHN HANCOCK
VARIABLE SERIES TRUST I AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH
FINANCIAL STATEMENTS.
</LEGEND>
<CIK> 0000785303
<NAME> JOHN HANCOCK VARIABLE SERIES TRUST I
<SERIES>
   <NUMBER> 05
   <NAME> MANAGED
<MULTIPLIER> 1000
       
<S>                             <C>
<PERIOD-TYPE>                   6-MOS
<FISCAL-YEAR-END>                          DEC-31-1998
<PERIOD-START>                             JAN-01-1998
<PERIOD-END>                               JUN-30-1998
<INVESTMENTS-AT-COST>                        2,562,354
<INVESTMENTS-AT-VALUE>                       3,124,609
<RECEIVABLES>                                  664,996
<ASSETS-OTHER>                                       0
<OTHER-ITEMS-ASSETS>                             8,257
<TOTAL-ASSETS>                               3,797,862
<PAYABLE-FOR-SECURITIES>                         4,596
<SENIOR-LONG-TERM-DEBT>                              0
<OTHER-ITEMS-LIABILITIES>                      646,580
<TOTAL-LIABILITIES>                            651,176
<SENIOR-EQUITY>                                      0
<PAID-IN-CAPITAL-COMMON>                     2,484,350
<SHARES-COMMON-STOCK>                          196,939
<SHARES-COMMON-PRIOR>                                0
<ACCUMULATED-NII-CURRENT>                        (921)
<OVERDISTRIBUTION-NII>                               0
<ACCUMULATED-NET-GAINS>                        135,896
<OVERDISTRIBUTION-GAINS>                             0
<ACCUM-APPREC-OR-DEPREC>                       527,361
<NET-ASSETS>                                 3,146,686
<DIVIDEND-INCOME>                               13,223
<INTEREST-INCOME>                               38,703
<OTHER-INCOME>                                       0
<EXPENSES-NET>                                   5,380
<NET-INVESTMENT-INCOME>                         46,546
<REALIZED-GAINS-CURRENT>                       135,896
<APPREC-INCREASE-CURRENT>                      182,065
<NET-CHANGE-FROM-OPS>                          364,507
<EQUALIZATION>                                       0
<DISTRIBUTIONS-OF-INCOME>                     (46,546)
<DISTRIBUTIONS-OF-GAINS>                             0
<DISTRIBUTIONS-OTHER>                                0
<NUMBER-OF-SHARES-SOLD>                          6,538
<NUMBER-OF-SHARES-REDEEMED>                    (7,762)
<SHARES-REINVESTED>                              3,024
<NET-CHANGE-IN-ASSETS>                         346,559
<ACCUMULATED-NII-PRIOR>                              0
<ACCUMULATED-GAINS-PRIOR>                            0
<OVERDISTRIB-NII-PRIOR>                              0
<OVERDIST-NET-GAINS-PRIOR>                           0
<GROSS-ADVISORY-FEES>                            4,818
<INTEREST-EXPENSE>                                   0
<GROSS-EXPENSE>                                  5,380
<AVERAGE-NET-ASSETS>                                 0
<PER-SHARE-NAV-BEGIN>                            14.35
<PER-SHARE-NII>                                   0.24
<PER-SHARE-GAIN-APPREC>                           1.63
<PER-SHARE-DIVIDEND>                            (0.24)
<PER-SHARE-DISTRIBUTIONS>                            0
<RETURNS-OF-CAPITAL>                                 0
<PER-SHARE-NAV-END>                              15.98
<EXPENSE-RATIO>                                   0.36
<AVG-DEBT-OUTSTANDING>                               0
<AVG-DEBT-PER-SHARE>                                 0
        

</TABLE>