Exhibit 32.1

                            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 Annual Report of Ultra Petroleum Corp. (the "Company") on
Form 10-K for the period ended December 31, 2004, as filed with the Securities
and Exchange Commission on the date hereof (the "Report"), I, Michael D.
Watford, Chairman, Chief Executive Officer, President and Chief Financial
Officer of the Company, certify, pursuant to 18 U.S.C. Section 1350, as adopted
pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, to the best of my
knowledge, that:

(1)   The Report fully complies with the requirements of Section 13(a) or 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.

Date: March 11, 2005            By: /s/ Michael D. Watford
                                    ----------------------
                                    Michael D. Watford
                                    Chairman, Chief Executive Officer,
                                    President and Chief Financial Officer

This certification is being furnished solely for purposes of compliance with 18
U.S.C. Section 1350 and shall not be deemed "filed" for purposes of Section 18
of the Securities Exchange Act of 1934, as amended, or otherwise subject to the
liabilities of that Section. Registration Statements or other documents filed
with the Securities and Exchange Commission shall not incorporate this exhibit
by reference, except as otherwise expressly stated in such filing.

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