
<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-31-1999
<PERIOD-START>                                 JAN-01-1999
<PERIOD-END>                                   DEC-31-1999
<CASH>                                         25,000
<SECURITIES>                                   0
<RECEIVABLES>                                  22,177,000
<ALLOWANCES>                                   850,000
<INVENTORY>                                    11,866,000
<CURRENT-ASSETS>                               36,477,000
<PP&E>                                         37,829,000
<DEPRECIATION>                                 15,650,000
<TOTAL-ASSETS>                                 58,656,000
<CURRENT-LIABILITIES>                          17,246,000
<BONDS>                                        6,630,000
<PREFERRED-MANDATORY>                          0
<PREFERRED>                                    0
<COMMON>                                       25,000
<OTHER-SE>                                     33,593,000
<TOTAL-LIABILITY-AND-EQUITY>                   58,656,000
<SALES>                                        128,035,000
<TOTAL-REVENUES>                               128,035,000
<CGS>                                          97,317,000
<TOTAL-COSTS>                                  112,058,000
<OTHER-EXPENSES>                               (238,000)
<LOSS-PROVISION>                               0
<INTEREST-EXPENSE>                             574,000
<INCOME-PRETAX>                                15,641,000
<INCOME-TAX>                                   5,944,000
<INCOME-CONTINUING>                            9,697,000
<DISCONTINUED>                                 0
<EXTRAORDINARY>                                0
<CHANGES>                                      0
<NET-INCOME>                                   9,697,000
<EPS-BASIC>                                  1.55
<EPS-DILUTED>                                  1.50


</TABLE>
