<ARTICLE> 9 <CIK> 0000799166 <NAME> MASSBANK CORP. <MULTIPLIER> 1,000 <PERIOD-TYPE> 12-MOS <FISCAL-YEAR-END> DEC-31-1998 <PERIOD-START> JAN-01-1998 <PERIOD-END> DEC-31-1998 <CASH> 7,038 <INT-BEARING-DEPOSITS> 2,033 <FED-FUNDS-SOLD> 148,207 <TRADING-ASSETS> 30,793 <INVESTMENTS-HELD-FOR-SALE> 418,126 <INVESTMENTS-CARRYING> 354 <INVESTMENTS-MARKET> 354 <LOANS> 304,989 <ALLOWANCE> (2,450) <TOTAL-ASSETS> 946,625 <DEPOSITS> 824,031 <SHORT-TERM> 1,438 <LIABILITIES-OTHER> 10,042 <LONG-TERM> 625 <PREFERRED-MANDATORY> 0 <PREFERRED> 0 <COMMON> 7,384 <OTHER-SE> 103,105 <TOTAL-LIABILITIES-AND-EQUITY> 946,625 <INTEREST-LOAN> 21,434 <INTEREST-INVEST> 29,625 <INTEREST-OTHER> 8,775 <INTEREST-TOTAL> 59,834 <INTEREST-DEPOSIT> 34,320 <INTEREST-EXPENSE> 34,320 <INTEREST-INCOME-NET> 25,514 <LOAN-LOSSES> 193 <SECURITIES-GAINS> 2,893 <EXPENSE-OTHER> 12,515 <INCOME-PRETAX> 17,396 <INCOME-PRE-EXTRAORDINARY> 17,396 <EXTRAORDINARY> 0 <CHANGES> 0 <NET-INCOME> 10,914 <EPS-PRIMARY> 3.09 <EPS-DILUTED> 2.97 <YIELD-ACTUAL> 2.81 <LOANS-NON> 1,004 <LOANS-PAST> 0 <LOANS-TROUBLED> 0 <LOANS-PROBLEM> 1,004 <ALLOWANCE-OPEN> 2,334 <CHARGE-OFFS> (103) <RECOVERIES> 26 <ALLOWANCE-CLOSE> 2,450 <ALLOWANCE-DOMESTIC> 1,966 <ALLOWANCE-FOREIGN> 0 <ALLOWANCE-UNALLOCATED> 484