
<TABLE> <S> <C>

<ARTICLE>                     5
<LEGEND>
THIS  SCHEDULE  CONTAINS  SUMMARY  FINANCIAL   INFORMATION  EXTRACTED  FROM  THE
CONSOLIDATED  FINANCIAL  STATEMENTS OF AAON,  INC., AS OF AND FOR THE YEAR ENDED
DECEMBER  31,  1998,  AND IS  QUALIFIED  IN ITS  ENTIRETY BY  REFERENCE  TO SUCH
FINANCIAL STATEMENTS.
</LEGEND>
       
<S>                             <C>
<PERIOD-TYPE>                   12-MOS
<FISCAL-YEAR-END>                              DEC-31-1998
<PERIOD-START>                                 JAN-01-1998
<PERIOD-END>                                   DEC-31-1998
<CASH>                                         25,000
<SECURITIES>                                   0
<RECEIVABLES>                                  18,343,000
<ALLOWANCES>                                   410,000
<INVENTORY>                                    12,160,000
<CURRENT-ASSETS>                               31,953,000
<PP&E>                                         31,231,000
<DEPRECIATION>                                 12,678,000
<TOTAL-ASSETS>                                 50,506,000
<CURRENT-LIABILITIES>                          14,832,000
<BONDS>                                        10,980,000
<PREFERRED-MANDATORY>                          0
<PREFERRED>                                    0
<COMMON>                                       25,000
<OTHER-SE>                                     24,386,000
<TOTAL-LIABILITY-AND-EQUITY>                   50,506,000
<SALES>                                        106,781,000
<TOTAL-REVENUES>                               106,781,000
<CGS>                                          86,952,000
<TOTAL-COSTS>                                  97,578,000
<OTHER-EXPENSES>                               (359,000)
<LOSS-PROVISION>                               0
<INTEREST-EXPENSE>                             1,017,000
<INCOME-PRETAX>                                8,545,000
<INCOME-TAX>                                   3,315,000
<INCOME-CONTINUING>                            8,545,000
<DISCONTINUED>                                 0
<EXTRAORDINARY>                                0
<CHANGES>                                      0
<NET-INCOME>                                   5,230,000
<EPS-PRIMARY>                                  .84
<EPS-DILUTED>                                  .82
        

</TABLE>
