<TABLE> <S> <C>

<PAGE>
 
<ARTICLE> 9
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM PATAPSCO
BANCORP, INC. AND SUBSIDIARY AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO
SUCH FINANCIAL STATEMENTS.
</LEGEND>
       
<S>                             <C>                     <C>
<PERIOD-TYPE>                   9-MOS                   3-MOS
<FISCAL-YEAR-END>                          JUN-30-1997             JUN-30-1997
<PERIOD-START>                             JUL-01-1996             JAN-01-1997
<PERIOD-END>                               MAR-31-1997             MAR-31-1997
<CASH>                                         174,978                 174,978
<INT-BEARING-DEPOSITS>                          52,052                  52,052
<FED-FUNDS-SOLD>                             6,672,170               6,672,170
<TRADING-ASSETS>                                     0                       0
<INVESTMENTS-HELD-FOR-SALE>                          0                       0
<INVESTMENTS-CARRYING>                       9,673,089               9,673,089
<INVESTMENTS-MARKET>                         9,673,089               9,673,089
<LOANS>                                     60,902,913              60,902,913
<ALLOWANCE>                                    347,157                 347,157
<TOTAL-ASSETS>                              79,918,710              79,918,710
<DEPOSITS>                                  65,497,890              65,497,890
<SHORT-TERM>                                         0                       0
<LIABILITIES-OTHER>                          1,785,238               1,785,238
<LONG-TERM>                                          0                       0
<PREFERRED-MANDATORY>                                0                       0
<PREFERRED>                                          0                       0
<COMMON>                                         3,626                   3,626
<OTHER-SE>                                  12,631,956              12,631,956
<TOTAL-LIABILITIES-AND-EQUITY>              79,918,710              79,918,710
<INTEREST-LOAN>                              3,403,793               1,183,085
<INTEREST-INVEST>                              568,468                 157,311
<INTEREST-OTHER>                               357,806                 126,215
<INTEREST-TOTAL>                             4,330,067               1,466,611
<INTEREST-DEPOSIT>                           2,019,077                 657,605
<INTEREST-EXPENSE>                           2,019,077                 657,605
<INTEREST-INCOME-NET>                        2,310,990                 809,006
<LOAN-LOSSES>                                  180,000                  60,000
<SECURITIES-GAINS>                               1,844                       0
<EXPENSE-OTHER>                              2,082,453                 570,369
<INCOME-PRETAX>                                213,914                 227,562
<INCOME-PRE-EXTRAORDINARY>                     213,914                 227,562
<EXTRAORDINARY>                                      0                       0
<CHANGES>                                            0                       0
<NET-INCOME>                                   731,103                 139,677
<EPS-PRIMARY>                                     2.17                    0.42
<EPS-DILUTED>                                     2.17                    0.42
<YIELD-ACTUAL>                                    7.46                    7.55
<LOANS-NON>                                    390,000                 390,000
<LOANS-PAST>                                   390,000                 390,000
<LOANS-TROUBLED>                                     0                       0
<LOANS-PROBLEM>                                      0                       0
<ALLOWANCE-OPEN>                               219,001                 313,743
<CHARGE-OFFS>                                   53,443                  27,297
<RECOVERIES>                                     1,599                     711
<ALLOWANCE-CLOSE>                              347,157                 347,157
<ALLOWANCE-DOMESTIC>                                 0                       0
<ALLOWANCE-FOREIGN>                                  0                       0
<ALLOWANCE-UNALLOCATED>                              0                       0
        

</TABLE>