<TABLE> <S> <C>

<ARTICLE> 9
<LEGEND>
This  schedule  contains  summary  financial   information  extracted  from  the
unaudited financial statements of SIS Bancorp,  Inc. at and for the period ended
June 30, 1997 and is qualified  in its  entirety by reference to such  financial
statements.
</LEGEND>
       
<S>                             <C>
<PERIOD-TYPE>                   6-MOS
<FISCAL-YEAR-END>                          DEC-31-1997
<PERIOD-START>                             JAN-01-1997
<PERIOD-END>                               JUN-30-1997
<CASH>                                          42,807
<INT-BEARING-DEPOSITS>                           5,585
<FED-FUNDS-SOLD>                                 5,000
<TRADING-ASSETS>                                     0
<INVESTMENTS-HELD-FOR-SALE>                    493,862
<INVESTMENTS-CARRYING>                         184,993
<INVESTMENTS-MARKET>                           184,424
<LOANS>                                        645,877
<ALLOWANCE>                                     16,392
<TOTAL-ASSETS>                               1,434,545
<DEPOSITS>                                   1,015,404
<SHORT-TERM>                                   277,687
<LIABILITIES-OTHER>                             35,511
<LONG-TERM>                                      2,670
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                            57
<OTHER-SE>                                     103,216
<TOTAL-LIABILITIES-AND-EQUITY>               1,434,545
<INTEREST-LOAN>                                 26,327
<INTEREST-INVEST>                               22,766
<INTEREST-OTHER>                                   359
<INTEREST-TOTAL>                                49,452
<INTEREST-DEPOSIT>                              16,879
<INTEREST-EXPENSE>                              24,403
<INTEREST-INCOME-NET>                           25,049
<LOAN-LOSSES>                                      801
<SECURITIES-GAINS>                                  11
<EXPENSE-OTHER>                                  7,241
<INCOME-PRETAX>                                  9,545
<INCOME-PRE-EXTRAORDINARY>                       9,545
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                     5,760
<EPS-PRIMARY>                                     1.03
<EPS-DILUTED>                                     1.02
<YIELD-ACTUAL>                                    7.55
<LOANS-NON>                                      5,479
<LOANS-PAST>                                       540
<LOANS-TROUBLED>                                   477
<LOANS-PROBLEM>                                      0
<ALLOWANCE-OPEN>                                15,597
<CHARGE-OFFS>                                      715
<RECOVERIES>                                       709
<ALLOWANCE-CLOSE>                               16,392
<ALLOWANCE-DOMESTIC>                            16,392
<ALLOWANCE-FOREIGN>                                  0
<ALLOWANCE-UNALLOCATED>                              0
        

</TABLE>