<ARTICLE> 9 <CIK> 0000799166 <NAME> MASSBANK CORP. <MULTIPLIER> 1,000 <PERIOD-TYPE> 6-MOS <FISCAL-YEAR-END> DEC-31-1998 <PERIOD-START> JAN-01-1998 <PERIOD-END> JUN-30-1998 <CASH> 7,065 <INT-BEARING-DEPOSITS> 2,596 <FED-FUNDS-SOLD> 146,315 <TRADING-ASSETS> 4,985 <INVESTMENTS-HELD-FOR-SALE> 445,280 <INVESTMENTS-CARRYING> 363 <INVESTMENTS-MARKET> 363 <LOANS> 287,921 <ALLOWANCE> (2,405) <TOTAL-ASSETS> 929,672 <DEPOSITS> 808,706 <SHORT-TERM> 1,334 <LIABILITIES-OTHER> 9,483 <LONG-TERM> 781 <PREFERRED-MANDATORY> 0 <PREFERRED> 0 <COMMON> 7,359 <OTHER-SE> 102,009 <TOTAL-LIABILITIES-AND-EQUITY> 929,672 <INTEREST-LOAN> 10,460 <INTEREST-INVEST> 15,662 <INTEREST-OTHER> 3,996 <INTEREST-TOTAL> 30,118 <INTEREST-DEPOSIT> 17,083 <INTEREST-EXPENSE> 17,083 <INTEREST-INCOME-NET> 13,035 <LOAN-LOSSES> 90 <SECURITIES-GAINS> 1,428 <EXPENSE-OTHER> 6,375 <INCOME-PRETAX> 8,917 <INCOME-PRE-EXTRAORDINARY> 8,917 <EXTRAORDINARY> 0 <CHANGES> 0 <NET-INCOME> 5,540 <EPS-PRIMARY> 1.56 <EPS-DILUTED> 1.50 <YIELD-ACTUAL> 2.89 <LOANS-NON> 1,752 <LOANS-PAST> 0 <LOANS-TROUBLED> 0 <LOANS-PROBLEM> 1,752 <ALLOWANCE-OPEN> 2,334 <CHARGE-OFFS> (26) <RECOVERIES> 7 <ALLOWANCE-CLOSE> 2,405 <ALLOWANCE-DOMESTIC> 2,258 <ALLOWANCE-FOREIGN> 0 <ALLOWANCE-UNALLOCATED> 147