Exhibit 99.1

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report of Questar Market Resources, Inc. (the “Company”) on Form 10-Q for the period ending March 31 2003, as filed with the Securities and Exchange Commission on the date hereof (the “Report”), Charles B. Stanley, President and Chief Executive Officer of the Company, and S. E. Parks, Vice President, Treasurer and Chief Financial Officer of the Company, each hereby certifies, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that, to the best of his knowledge:

(1)  The Report fully complies with the requirements of Section 13(a) or Section 15(d) of the Securities Exchange Act of 1934; and

(2)  The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

	QUESTAR MARKET RESOURCES, INC.
May 14, 2003	/s/Charles B. Stanley
	Charles B. Stanley
	President and Chief Executive Officer
May 14, 2003	/s/S. E. Parks
	S. E. Parks
	Vice President, Treasurer and Chief Financial Officer

A signed original of this written statement required by Section 906 has been provided to the Company and will be retained by the Company and furnished to the Securities and Exchange Commission or its staff upon request.

This certification accompanies the Report pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 and shall not, except to the extent required by the Sarbanes-Oxley Act of 2002, be deemed filed by the Company for purposes of Section 18 of the Securities Exchange Act of 1934, as amended.

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