EXHIBIT (12)(a) ONEOK, Inc. Computation of Ratio of Earnings to Fixed Charges For the Three Months Ended March 31, 2000 1999 - -------------------------------------------------------------------------------- (Thousands of Dollars) Fixed Charges, as defined Interest on long-term debt $ 16,220 $ 8,575 Other interest 5,151 3,559 Amortization of debt discount and expense 614 448 Interest on lease agreements 620 651 - -------------------------------------------------------------------------------- Total Fixed Charges 22,605 13,233 - -------------------------------------------------------------------------------- Earnings before income taxes and income from equity investees 98,117 99,168 - -------------------------------------------------------------------------------- Earnings available for fixed charges $ 120,722 $ 112,401 ================================================================================ Ratio of earnings to combined fixed charges 5.34x 8.49x ================================================================================ For purposes of computing the ratio of earnings to fixed charges, "earnings" consists of income before cumulative effect of a change in accounting principle plus fixed charges and income taxes, less undistributed income from equity investees. "Fixed charges" consists of interest charges, the amortization of debt discounts and issue costs and the representative interest portion of operating leases. 1