<ARTICLE> 9 <CIK> 0000799166 <NAME> MASSBANK CORP. <MULTIPLIER> 1,000 <PERIOD-TYPE> 9-MOS <FISCAL-YEAR-END> DEC-31-1997 <PERIOD-START> JAN-01-1997 <PERIOD-END> SEP-30-1997 <CASH> 5,160 <INT-BEARING-DEPOSITS> 2,554 <FED-FUNDS-SOLD> 117,180 <TRADING-ASSETS> 12,510 <INVESTMENTS-HELD-FOR-SALE> 490,967 <INVESTMENTS-CARRYING> 377 <INVESTMENTS-MARKET> 377 <LOANS> 268,538 <ALLOWANCE> (2,254) <TOTAL-ASSETS> 932,757 <DEPOSITS> 820,934 <SHORT-TERM> 1,608 <LIABILITIES-OTHER> 8,708 <LONG-TERM> 937 <COMMON> 7,322 <PREFERRED-MANDATORY> 0 <PREFERRED> 0 <OTHER-SE> 93,248 <TOTAL-LIABILITIES-AND-EQUITY> 932,757 <INTEREST-LOAN> 14,769 <INTEREST-INVEST> 25,037 <INTEREST-OTHER> 5,431 <INTEREST-TOTAL> 45,237 <INTEREST-DEPOSIT> 25,841 <INTEREST-EXPENSE> 25,841 <INTEREST-INCOME-NET> 19,396 <LOAN-LOSSES> 170 <SECURITIES-GAINS> 1,501 <EXPENSE-OTHER> 10,310 <INCOME-PRETAX> 11,837 <INCOME-PRE-EXTRAORDINARY> 11,837 <EXTRAORDINARY> 0 <CHANGES> 0 <NET-INCOME> 7,511 <EPS-PRIMARY> 2.05 <EPS-DILUTED> 2.05 <YIELD-ACTUAL> 2.93 <LOANS-NON> 1,163 <LOANS-PAST> 527 <LOANS-TROUBLED> 0 <LOANS-PROBLEM> 1,690 <ALLOWANCE-OPEN> 2,237 <CHARGE-OFFS> (288) <RECOVERIES> 35 <ALLOWANCE-CLOSE> 2,254 <ALLOWANCE-DOMESTIC> 1,825 <ALLOWANCE-FOREIGN> 0 <ALLOWANCE-UNALLOCATED> 429