<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> 23
   <NAME> HIGH YIELD BOND
<MULTIPLIER> 1000
       
<S>                             <C>
<PERIOD-TYPE>                   8-MOS
<FISCAL-YEAR-END>                          DEC-31-1998
<PERIOD-START>                             MAY-01-1998
<PERIOD-END>                               DEC-31-1998
<INVESTMENTS-AT-COST>                           14,870
<INVESTMENTS-AT-VALUE>                          14,509
<RECEIVABLES>                                      308
<ASSETS-OTHER>                                       0
<OTHER-ITEMS-ASSETS>                                 0
<TOTAL-ASSETS>                                  14,817
<PAYABLE-FOR-SECURITIES>                            27
<SENIOR-LONG-TERM-DEBT>                              0
<OTHER-ITEMS-LIABILITIES>                            1
<TOTAL-LIABILITIES>                                 28
<SENIOR-EQUITY>                                      0
<PAID-IN-CAPITAL-COMMON>                        15,355
<SHARES-COMMON-STOCK>                            1,602
<SHARES-COMMON-PRIOR>                                0
<ACCUMULATED-NII-CURRENT>                            0
<OVERDISTRIBUTION-NII>                               0
<ACCUMULATED-NET-GAINS>                              0
<OVERDISTRIBUTION-GAINS>                             0
<ACCUM-APPREC-OR-DEPREC>                         (566)
<NET-ASSETS>                                    14,789
<DIVIDEND-INCOME>                                    7
<INTEREST-INCOME>                                  626
<OTHER-INCOME>                                       0
<EXPENSES-NET>                                      68
<NET-INVESTMENT-INCOME>                            565
<REALIZED-GAINS-CURRENT>                             7
<APPREC-INCREASE-CURRENT>                        (566)
<NET-CHANGE-FROM-OPS>                                6
<EQUALIZATION>                                       0
<DISTRIBUTIONS-OF-INCOME>                        (565)
<DISTRIBUTIONS-OF-GAINS>                           (7)
<DISTRIBUTIONS-OTHER>                                0
<NUMBER-OF-SHARES-SOLD>                          1,741
<NUMBER-OF-SHARES-REDEEMED>                      (200)
<SHARES-REINVESTED>                                 61
<NET-CHANGE-IN-ASSETS>                          14,789
<ACCUMULATED-NII-PRIOR>                              0
<ACCUMULATED-GAINS-PRIOR>                            0
<OVERDISTRIB-NII-PRIOR>                              0
<OVERDIST-NET-GAINS-PRIOR>                           0
<GROSS-ADVISORY-FEES>                               49
<INTEREST-EXPENSE>                                   0
<GROSS-EXPENSE>                                    153
<AVERAGE-NET-ASSETS>                            11,329
<PER-SHARE-NAV-BEGIN>                            10.00
<PER-SHARE-NII>                                   0.46
<PER-SHARE-GAIN-APPREC>                         (0.76)
<PER-SHARE-DIVIDEND>                            (0.46)
<PER-SHARE-DISTRIBUTIONS>                       (0.01)
<RETURNS-OF-CAPITAL>                                 0
<PER-SHARE-NAV-END>                               9.23
<EXPENSE-RATIO>                                      0
<AVG-DEBT-OUTSTANDING>                               0
<AVG-DEBT-PER-SHARE>                                 0
        

</TABLE>