<ARTICLE> 9
<CIK> 0000799166
<NAME> MASSBANK CORP.
<MULTIPLIER> 1,000
       
                             
<PERIOD-TYPE>                   12-MOS
<FISCAL-YEAR-END>                          DEC-31-1997
<PERIOD-START>                             JAN-01-1997
<PERIOD-END>                               DEC-31-1997
<CASH>                                           6,808
<INT-BEARING-DEPOSITS>                           2,083
<FED-FUNDS-SOLD>                               105,241
<TRADING-ASSETS>                                21,260
<INVESTMENTS-HELD-FOR-SALE>                    482,224
<INVESTMENTS-CARRYING>                             372
<INVESTMENTS-MARKET>                               372
<LOANS>                                        272,303
<ALLOWANCE>                                    (2,334)
<TOTAL-ASSETS>                                 925,403
<DEPOSITS>                                     809,850
<SHORT-TERM>                                     1,502
<LIABILITIES-OTHER>                              9,491
<LONG-TERM>                                        781
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                         7,337
<OTHER-SE>                                      96,442
<TOTAL-LIABILITIES-AND-EQUITY>                 925,403
<INTEREST-LOAN>                                 19,928
<INTEREST-INVEST>                               33,488
<INTEREST-OTHER>                                 7,317
<INTEREST-TOTAL>                                60,733
<INTEREST-DEPOSIT>                              34,681
<INTEREST-EXPENSE>                              34,681
<INTEREST-INCOME-NET>                           26,052
<LOAN-LOSSES>                                      260
<SECURITIES-GAINS>                               1,939
<EXPENSE-OTHER>                                 13,425
<INCOME-PRETAX>                                 16,165
<INCOME-PRE-EXTRAORDINARY>                      16,165
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                    10,167
<EPS-PRIMARY>                                     2.88
<EPS-DILUTED>                                     2.77
<YIELD-ACTUAL>                                    2.93
<LOANS-NON>                                      1,771
<LOANS-PAST>                                         0
<LOANS-TROUBLED>                                     0
<LOANS-PROBLEM>                                  1,771
<ALLOWANCE-OPEN>                                 2,237
<CHARGE-OFFS>                                    (327)
<RECOVERIES>                                        59
<ALLOWANCE-CLOSE>                                2,334
<ALLOWANCE-DOMESTIC>                             1,716
<ALLOWANCE-FOREIGN>                                  0
<ALLOWANCE-UNALLOCATED>                            618