<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE
CONSOLIDATED STATEMENT OF EARNINGS FOR THE 1998 FISCAL YEAR'S SECOND QUARTER
ENDED FEBRUARY 28, 1999, AND THE CONSOLIDATED BALANCE SHEET AT AUGUST 31, 1998,
FOR ONEOK INC. AND SUBSIDIARIES AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO
SUCH FINANCIAL STATEMENTS.
</LEGEND>
<MULTIPLIER> 1,000
       
                             
<PERIOD-TYPE>                   6-MOS
<FISCAL-YEAR-END>                          AUG-31-1999
<PERIOD-START>                             SEP-01-1998
<PERIOD-END>                               FEB-28-1999
<CASH>                                          18,357
<SECURITIES>                                         0
<RECEIVABLES>                                  332,214
<ALLOWANCES>                                         0
<INVENTORY>                                     84,016
<CURRENT-ASSETS>                               457,494
<PP&E>                                       2,680,361
<DEPRECIATION>                                 945,461
<TOTAL-ASSETS>                               2,696,786
<CURRENT-LIABILITIES>                          461,430
<BONDS>                                              0
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                    569,069
<COMMON>                                       647,497
<OTHER-SE>                                   1,216,566
<TOTAL-LIABILITY-AND-EQUITY>                 2,696,786
<SALES>                                              0
<TOTAL-REVENUES>                               972,593
<CGS>                                                0
<TOTAL-COSTS>                                  603,124
<OTHER-EXPENSES>                                     0
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                              23,364
<INCOME-PRETAX>                                136,765
<INCOME-TAX>                                    53,983
<INCOME-CONTINUING>                             82,782
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                    82,782
<EPS-PRIMARY>                                     2.03
<EPS-DILUTED>                                     1.60