<ARTICLE> 9 <CIK> 0000799166 <NAME> MASSBANK CORP. <MULTIPLIER> 1,000 <PERIOD-TYPE> 6-MOS <FISCAL-YEAR-END> DEC-31-1999 <PERIOD-START> JAN-01-1999 <PERIOD-END> JUN-30-1999 <CASH> 6,992 <INT-BEARING-DEPOSITS> 3,549 <FED-FUNDS-SOLD> 116,235 <TRADING-ASSETS> 5,980 <INVESTMENTS-HELD-FOR-SALE> 446,372 <INVESTMENTS-CARRYING> 230 <INVESTMENTS-MARKET> 230 <LOANS> 331,796 <ALLOWANCE> (2,558) <TOTAL-ASSETS> 946,016 <DEPOSITS> 829,290 <SHORT-TERM> 1,350 <LIABILITIES-OTHER> 10,399 <LONG-TERM> 625 <PREFERRED-MANDATORY> 0 <PREFERRED> 0 <COMMON> 7,391 <OTHER-SE> 96,961 <TOTAL-LIABILITIES-AND-EQUITY> 946,016 <INTEREST-LOAN> 11,184 <INTEREST-INVEST> 13,525 <INTEREST-OTHER> 4,009 <INTEREST-TOTAL> 28,718 <INTEREST-DEPOSIT> 16,448 <INTEREST-EXPENSE> 16,448 <INTEREST-INCOME-NET> 12,270 <LOAN-LOSSES> 110 <SECURITIES-GAINS> 2,509 <EXPENSE-OTHER> 6,290 <INCOME-PRETAX> 9,189 <INCOME-PRE-EXTRAORDINARY> 9,189 <EXTRAORDINARY> 0 <CHANGES> 0 <NET-INCOME> 5,779 <EPS-BASIC> 1.69 <EPS-DILUTED> 1.64 <YIELD-ACTUAL> 2.66 <LOANS-NON> 959 <LOANS-PAST> 0 <LOANS-TROUBLED> 0 <LOANS-PROBLEM> 959 <ALLOWANCE-OPEN> 2,450 <CHARGE-OFFS> (5) <RECOVERIES> 3 <ALLOWANCE-CLOSE> 2,558 <ALLOWANCE-DOMESTIC> 2,471 <ALLOWANCE-FOREIGN> 0 <ALLOWANCE-UNALLOCATED> 87