<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE
CONSOLIDATED CONDENSED STATEMENT OF INCOME FOR THE 1999 FISCAL YEAR'S NINE
MONTHS ENDED MAY 31, 1999, AND THE CONSOLIDATED CONDENSED BALANCE SHEET AT MAY
31, 1999 FOR ONEOK, INC. AND SUBSIDIARIES AND IS QUALIFIED IN ITS ENTIRETY BY
REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
<MULTIPLIER> 1,000

                             
<PERIOD-TYPE>                   9-MOS
<FISCAL-YEAR-END>                          AUG-31-1999
<PERIOD-START>                             SEP-01-1998
<PERIOD-END>                               MAY-31-1999
<CASH>                                           6,759
<SECURITIES>                                         0
<RECEIVABLES>                                  222,287
<ALLOWANCES>                                         0
<INVENTORY>                                    102,209
<CURRENT-ASSETS>                               374,168
<PP&E>                                       3,010,539
<DEPRECIATION>                                 966,719
<TOTAL-ASSETS>                               2,935,163
<CURRENT-LIABILITIES>                          687,291
<BONDS>                                              0
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                    569,070
<COMMON>                                       648,555
<OTHER-SE>                                           0
<TOTAL-LIABILITY-AND-EQUITY>                 2,935,163
<SALES>                                              0
<TOTAL-REVENUES>                             1,385,718
<CGS>                                                0
<TOTAL-COSTS>                                  862,397
<OTHER-EXPENSES>                                     0
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                              36,349
<INCOME-PRETAX>                                168,946
<INCOME-TAX>                                    64,968
<INCOME-CONTINUING>                            103,978
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                   103,978
<EPS-BASIC>                                       2.41
<EPS-DILUTED>                                     2.01