<ARTICLE> 9 <CIK> 0000799166 <NAME> MASSBANK CORP. <MULTIPLIER> 1,000 <PERIOD-TYPE> 12-MOS <FISCAL-YEAR-END> DEC-31-1999 <PERIOD-START> JAN-01-1999 <PERIOD-END> DEC-31-1999 <CASH> 10,476 <INT-BEARING-DEPOSITS> 3,841 <FED-FUNDS-SOLD> 86,211 <TRADING-ASSETS> 6,042 <INVESTMENTS-HELD-FOR-SALE> 457,502 <INVESTMENTS-CARRYING> 230 <INVESTMENTS-MARKET> 230 <LOANS> 325,265 <ALLOWANCE> 2,555 <TOTAL-ASSETS> 924,716 <DEPOSITS> 818,057 <SHORT-TERM> 1,477 <LIABILITIES-OTHER> 3,235 <LONG-TERM> 468 <PREFERRED-MANDATORY> 0 <PREFERRED> 0 <COMMON> 7,407 <OTHER-SE> 94,072 <TOTAL-LIABILITIES-AND-EQUITY> 924,716 <INTEREST-LOAN> 22,772 <INTEREST-INVEST> 28,020 <INTEREST-OTHER> 7,414 <INTEREST-TOTAL> 58,206 <INTEREST-DEPOSIT> 33,204 <INTEREST-EXPENSE> 33,204 <INTEREST-INCOME-NET> 25,002 <LOAN-LOSSES> 140 <SECURITIES-GAINS> 4,033 <EXPENSE-OTHER> 12,566 <INCOME-PRETAX> 17,858 <INCOME-PRE-EXTRAORDINARY> 17,858 <EXTRAORDINARY> 0 <CHANGES> 0 <NET-INCOME> 11,311 <EPS-BASIC> 3.35 <EPS-DILUTED> 3.25 <YIELD-ACTUAL> 2.72 <LOANS-NON> 795 <LOANS-PAST> 0 <LOANS-TROUBLED> 0 <LOANS-PROBLEM> 795 <ALLOWANCE-OPEN> 2,450 <CHARGE-OFFS> 76 <RECOVERIES> 41 <ALLOWANCE-CLOSE> 2,555 <ALLOWANCE-DOMESTIC> 2,058 <ALLOWANCE-FOREIGN> 0 <ALLOWANCE-UNALLOCATED> 497