1 EXHIBIT 5.1 WINSTEAD SECHREST & MINICK P.C. 5400 Renaissance Tower 1201 Elm Street Dallas, Texas 75270-2199 214/745-5400 PH 214/745-5390 FAX August 16, 2001 Chesapeake Energy Corporation 6100 North Western Avenue Oklahoma City, OK 73118 Re: Chesapeake Energy Corporation 2001 NonQualified Stock Option Plan Ladies and Gentlemen: We have examined the Registration Statement on Form S-8 to be filed by you with the Securities and Exchange Commission in connection with the Chesapeake Energy Corporation 2001 NonQualified Stock Option Plan (the "Plan"), which Registration Statement covers the offer and sale of shares of common stock, par value $.01 per share (the "Shares"), of Chesapeake Energy Corporation to be issued by Chesapeake Energy Corporation pursuant to the Plan. We have also examined your minute books and other corporate records, and have made such other investigation as we have deemed necessary in order to render the opinions expressed herein. Based on the foregoing, we are of the opinion that the Shares, when issued in accordance with the terms of the Plan, will be legally issued, fully paid and nonassessable in accordance with the Oklahoma General Corporation Act. Consent is hereby given for the inclusion of this opinion as part of the referenced Registration Statement. Very truly yours, /s/ Winstead Sechrest & Minick P.C. Winstead Sechrest & Minick P.C.