<ARTICLE> 9 <CIK> 0000799166 <NAME> MASSBANK CORP. <MULTIPLIER> 1,000 <PERIOD-TYPE> 3-MOS <FISCAL-YEAR-END> DEC-31-1999 <PERIOD-START> JAN-01-1999 <PERIOD-END> MAR-31-1999 <CASH> 7,689 <INT-BEARING-DEPOSITS> 1,511 <FED-FUNDS-SOLD> 144,191 <TRADING-ASSETS> 15,944 <INVESTMENTS-HELD-FOR-SALE> 425,615 <INVESTMENTS-CARRYING> 349 <INVESTMENTS-MARKET> 349 <LOANS> 312,150 <ALLOWANCE> (2,500) <TOTAL-ASSETS> 941,859 <DEPOSITS> 822,001 <SHORT-TERM> 1,546 <LIABILITIES-OTHER> 9,420 <LONG-TERM> 625 <PREFERRED-MANDATORY> 0 <PREFERRED> 0 <COMMON> 7,386 <OTHER-SE> 100,881 <TOTAL-LIABILITIES-AND-EQUITY> 941,859 <INTEREST-LOAN> 5,560 <INTEREST-INVEST> 6,832 <INTEREST-OTHER> 1,981 <INTEREST-TOTAL> 14,373 <INTEREST-DEPOSIT> 8,233 <INTEREST-EXPENSE> 8,233 <INTEREST-INCOME-NET> 6,140 <LOAN-LOSSES> 50 <SECURITIES-GAINS> 1,378 <EXPENSE-OTHER> 3,168 <INCOME-PRETAX> 4,663 <INCOME-PRE-EXTRAORDINARY> 4,663 <EXTRAORDINARY> 0 <CHANGES> 0 <NET-INCOME> 2,913 <EPS-PRIMARY> 0.84 <EPS-DILUTED> 0.82 <YIELD-ACTUAL> 2.67 <LOANS-NON> 732 <LOANS-PAST> 0 <LOANS-TROUBLED> 0 <LOANS-PROBLEM> 732 <ALLOWANCE-OPEN> 2,450 <CHARGE-OFFS> (1) <RECOVERIES> 1 <ALLOWANCE-CLOSE> 2,500 <ALLOWANCE-DOMESTIC> 1,734 <ALLOWANCE-FOREIGN> 0 <ALLOWANCE-UNALLOCATED> 766