<PAGE>

                                                                    EXHIBIT 10.1

                               SECOND AMENDMENT
                                       TO
                   FIRST AMENDED AND RESTATED CREDIT AGREEMENT

         This Second Amendment ("Second Amendment") to First Amended and
Restated Credit Agreement dated as of March 1, 2002, as amended by the First
Amendment to First Amended and Restated Credit Agreement dated November 4, 2002
and the Letter Agreement dated February 18, 2003 ("Credit Agreement") by and
among ULTRA RESOURCES, INC., a Wyoming corporation ("Borrower"), the several
banks and financial institutions from time to time parties to this Credit
Agreement (the "Banks," such term to include all undersigned Banks and all other
financial institutions which subsequently become parties to this Agreement in
accordance with Section 9.05 hereof), BANK ONE, NA, a national banking
association ("Bank One") as a Bank, as the LC Issuer (hereinafter defined) and
as Administrative Agent for the Banks (in such latter capacity and together with
its successors and permitted assigns in such capacity, the "Administrative
Agent"), is entered into this 14th day of May, 2003.

                              W I T N E S S E T H:

         WHEREAS, Borrower and the Banks desire to amend the Credit Agreement as
set forth herein;

         NOW, THEREFORE, in consideration of the premises and for Ten Dollars
($10.00) and other good and valuable consideration received by each party
hereto, and each intending to be legally bound hereby, the parties agree as
follows:

         I. Amendments to Credit Agreement.

         Article I, DEFINITIONS, of the Credit Agreement is hereby amended by
replacing each definition in its entirety with the following definition:

         "Facility Termination Date" means March 1, 2006.

         "Note" and "Notes" means, individually, a promissory note issued by
         Borrower payable to the order of a Bank evidencing the Loans made by
         that Bank pursuant to Section 2.01 hereof and being substantially in
         the form of the note attached as Exhibit B hereto, but specifically
         including each Amended and Restated Note attached to the Second
         Amendment at Exhibits A-1 through A-6, together with any and all
         further renewals, extensions for any period, increases or
         rearrangements thereof, and means collectively all of such Notes.

         Article I, DEFINITIONS, of the Credit Agreement is hereby amended by
adding thereto the following defined term:

          "Second Amendment" means the Second Amendment to Amended and Restated
         Credit Agreement dated May 14, 2003 among the Banks and Borrower.

<PAGE>

         Section 2.06, Borrowing Base Determination, is hereby amended by
replacing the first sentence thereto with the following sentence:

         "The Borrowing Base in effect as of May 14, 2003 is equal to One
         Hundred Fifty-Five Million Dollars ($155,000,000.00) relative to the
         Proved Reserves attributable to the Borrowing Base Oil and Gas
         Properties described on Exhibit "A" attached hereto, as such Exhibit
         "A" may be amended or supplemented from time to time."

         Section 6.16, EBITDA to Interest Ratio, is hereby amended by revising
that section in its entirety to read as follows:

         "(a) Permit, as of the end of any fiscal quarter, the ratio of EBITDA
         to total interest expense on all Indebtedness, calculated based on the
         Consolidated Financial Statements, to be less than 3.5 to 1.0,
         calculated on a rolling four-quarter basis, and (b) permit, as of the
         end of any fiscal quarter, the ratio of Borrower's EBITDA to Borrower's
         total interest expense on all of Borrower's Indebtedness, calculated
         based solely on the consolidating financial statements relative to
         Borrower, which constitute a part of the Consolidated Financial
         Statements, to be less than 3.5 to 1.0, calculated on a rolling
         four-quarter basis."

          Section 6.17, General and Administrative Expenses, is hereby amended
 revising that section in its entirety to read as follows:

         "This section is intentionally omitted."

          Section 6.18, Intercompany Transfers, is hereby amended by replacing
 the text in that section immediately preceding the proviso therein with the
 following text:

         "Permit the Borrower or any of its Affiliates to invest in, loan to or
         transfer to Sino-American Energy Corporation an amount greater than
         Twenty-Five Million Dollars ($25,000,000) during the calendar year
         ending December 31, 2003 without the prior written approval of the
         Required Banks; and thereafter permit the Borrower or any of its
         Affiliates to invest in or transfer to Sino-American Energy Corporation
         an amount greater than Thirty-Five Million Dollars ($35,000,000) during
         each subsequent calendar year without the prior written approval of the
         Required Banks;"

          Exhibit C attached to the Credit Agreement is hereby replaced in its
 entirety with Exhibit C attached to this Second Amendment. Any reference to
 Exhibit C in the Credit Agreement or any other Loan Document shall be deemed to
 refer to Exhibit C attached to this Second Amendment.

          Schedule l.Ol(b) attached to the Credit Agreement, as replaced
 pursuant to the First Amendment, is hereby replaced in its entirety with
 Schedule 1.01(b) attached to this Second Amendment. Any reference to Schedule
 1.01(b) in the Credit Agreement or any other Loan Document shall be deemed to
 refer to Schedule 1.01(b) attached to this Second Amendment.

                                        2
<PAGE>

         II.      Conditions Precedent in Connection with the Second Amendment.
The Second Amendment shall not be binding on the Banks until satisfaction of the
following conditions precedent:

         A.       Administrative Agent shall have received fully executed
         counterparts, in the number of multiple originals requested by
         Administrative Agent, of the Second Amendment, duly executed by an
         authorized officer for Borrower.

         B.       Administrative Agent shall have received from Borrower,
         contemporaneously with the Borrower's execution of this Second
         Amendment for the benefit of the Banks, a fee in the amount of $150,000
         in connection with the extension of the Borrowing Base in effect prior
         to this Second Amendment and a fee in the amount of $131,250 in
         connection with the increased Borrowing Base pursuant to this Second
         Amendment.

         C.       Administrative Agent shall have received from Borrower the
         replacement Notes payable to each respective Bank in the forms attached
         to this Second Amendment as Exhibits A-1 through A-6.

         D.       The representations and warranties contained in Article IV of
         the Credit Agreement shall be true and correct in all material respects
         on the date of the Second Amendment with the same effect as though such
         representations and warranties had been made on such date; and no Event
         of Default shall have occurred and be continuing or will have occurred
         upon the execution of the Second Amendment.

         E.       All legal matters incident to the consummation of the
         transactions contemplated by the Second Amendment shall be satisfactory
         to the firm of Porter & Hedges, L.L.P., special counsel for Bank.

         F.       All reasonable and documented legal fees owed by Banks to
         Porter & Hedges, L.L.P. in connection with the Second Amendment shall
         have been paid by Borrower.

         III.     Post-Closing Covenant. Each Bank hereby agrees to deliver, as
soon as reasonably practical, each Note executed and delivered by Borrower to
each Bank dated as of November 4, 2002 endorsed with the following language:
"Replaced by Note dated May 14, 2003, in the face amount of $_____________, made
by the maker and payable to the payee hereof," with such dollar amount being
equal to the face amount of the Note payable to each respective Bank as set
forth on Schedule 1.Ol(b) attached to this Second Amendment.

         IV.      Reaffirmation of Representations and Warranties. To induce the
Banks to enter into this Second Amendment, the Borrower hereby reaffirms, as of
the date hereof, its representations and warranties contained in Article IV of
the Credit Agreement and in all other documents executed pursuant thereto, and
additionally represents and warrants as follows:

         A.       The execution and delivery of this Second Amendment and the
         performance by the Borrower of its obligations under this Second
         Amendment are within the Borrower's power, have been duly authorized by
         all necessary corporate action, have received all necessary
         governmental approval (if any shall be required), and do not and will
         not

                                        3
<PAGE>

         contravene or conflict with any provision of law or of the charter or
         by-laws of the Borrower or of any agreement binding upon the Borrower.

         B.       The Credit Agreement as amended by this Second Amendment
         represents the legal, valid and binding obligations of the Borrower,
         enforceable against the Borrower in accordance with their respective
         terms subject as to enforcement only to bankruptcy, insolvency,
         reorganization, moratorium or other similar laws affecting the
         enforcement of creditors' rights generally.

         C.       No Event of Default or Unmatured Event of Default has occurred
         and is continuing as of the date hereof.

         V.       Defined Terms. Except as amended hereby, terms used herein
that are defined in the Credit Agreement shall have the same meanings herein.

         VI.      Reaffirmation of Credit Agreement. This Second Amendment shall
be deemed to be an amendment to the Credit Agreement, and the Credit Agreement,
as further amended hereby, is hereby ratified, approved and confirmed in each
and every respect. All references to the Credit Agreement herein and in any
other document, instrument, agreement or writing shall hereafter be deemed to
refer to the Credit Agreement as amended hereby.

         VII.     Entire Agreement. The Credit Agreement, as hereby amended,
embodies the entire agreement between the Borrower and the Banks and supersedes
all prior proposals, agreements and understandings relating to the subject
matter hereof. The Borrower certifies that it is relying on no representation,
warranty, covenant or agreement except for those set forth in the Credit
Agreement, as hereby amended, and in the other documents previously executed or
executed of even date herewith.

         VIII.    Governing Law. THIS SECOND AMENDMENT SHALL BE GOVERNED BY AND
CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF TEXAS AND THE APPLICABLE
LAWS OF THE UNITED STATES OF AMERICA.

         IX.      Severability. Whenever possible each provision of this Second
Amendment shall be interpreted in such manner as to be effective and valid under
applicable law, but if any provision of this Second Amendment shall be
prohibited by or invalid under applicable law, such provision shall be
ineffective to the extent of such prohibition or invalidity, without
invalidating the remainder of such provision or the remaining provisions of this
Second Amendment.

         X.       Execution in Counterparts. This Second Amendment may be
executed in any number of counterparts and by the different parties on separate
counterparts, and each such counterpart shall be deemed to be an original, but
all such counterparts shall together constitute but one and the same agreement.

         XI.      Section Captions. Section captions used in this Second
Amendment are for convenience of reference only, and shall not affect the
construction of this Second Amendment.

                                        4
<PAGE>

         XII.     Successors and Assigns. This Second Amendment shall be binding
upon the Borrower and the Banks and their respective successors and assigns, and
shall inure to the benefit of the Borrower and the Banks, and the respective
successors and assigns of the Banks.

         XIII.    Non-Application of Chapter 346 of Texas Finance Codes. In no
event shall Chapter 346 of the Texas Finance Code (which regulates certain
revolving loan accounts and revolving tri-party accounts) apply to this Credit
Agreement as hereby further amended or any other Loan Documents or the
transactions contemplated hereby.

         XIV.     NOTICE. THIS SECOND AMENDMENT TOGETHER WITH THE LOAN
AGREEMENT, AND THE OTHER SECURITY INSTRUMENTS REPRESENT THE FINAL AGREEMENT
BETWEEN THE PARTIES AND MAY NOT BE CONTRADICTED BY EVIDENCE OF PRIOR,
CONTEMPORANEOUS OR SUBSEQUENT ORAL AGREEMENTS OF THE PARTIES. THERE ARE NO
WRITTEN ORAL AGREEMENTS BETWEEN THE PARTIES.

                            [SIGNATURE PACES FOLLOW]

                                        5
<PAGE>

IN WITNESS WHEREOF, the parties hereto have caused this Second Amendment to be
duly executed as of the day and year first above written.

                                     BORROWER

                                     ULTRA RESOURCES, INC.

                                     By: /s/ Michael D. Watford
                                         ---------------------------------------
                                           Michael D. Watford
                                           President and Chief Executive Officer

                                     ADMINISTRATIVE AGENT, LC ISSUER AND BANK:

                                     BANK ONE, NA

                                     By: /s/ Stephen Shatto
                                         ---------------------------------------
                                           Stephen Shatto
                                           Vice President

                                     SYNDICATION AGENT AND BANK:

                                     UNION BANK OF CALIFORNIA, N.A.

                                     By: /s/ Damien Meiburger
                                         ---------------------------------------
                                           Damien Meiburger
                                           Senior Vice President

                                     By: /s/ Ali Ahmed
                                         ---------------------------------------
                                           Ali Ahmed
                                           Vice President

                                        6
<PAGE>

                                     CO-AGENT AND BANK:

                                     HIBERNIA NATIONAL BANK

                                     By: /s/ Nancy G. Moragas
                                         ---------------------------------------
                                           Nancy G. Moragas
                                           Vice President

                                     CO-AGENT AND BANK:

                                     GUARANTY BANK, FSB

                                     By: /s/ Richard E. Menchaca
                                         ---------------------------------------
                                           Richard E. Menchaca
                                           Vice President

                                     BANK:

                                     COMPASS BANK

                                     By: /s/ Kathleen J. Bowen
                                         ---------------------------------------
                                           Kathleen J. Bowen
                                           Vice President

                                     BANK:

                                     BANK OF SCOTLAND

                                     By: /s/ Joseph Fratus
                                         ---------------------------------------
                                           Joseph Fratus
                                           First Vice President

                                        7
<PAGE>

                                SCHEDULE 1.01(b)

               Commitment Amounts and Aggregate Commitment Amount

<TABLE>
<CAPTION>
                                                 Percentage                         Commitment
          Bank                                     Share                              Amount
          ----                                     -----                              ------
<S>                                              <C>                             <C>
Bank One, NA                                       21.94%                        $ 54,838,709.68

Union Bank of California, N.A.                     21.94%                        $ 54,838,709.68

Hibernia National Bank                             14.19%                        $ 35,483,870.97

Guaranty Bank, FSB                                 21.94%                        $ 54,838,709.68

Compass Bank                                        9.03%                        $ 22,580,645.16

Bank of Scotland                                   10.97%                        $ 27,419,354.84

Aggregate Commitment Amount:                                                     $250,000,000.00
</TABLE>

                                        8

<PAGE>

                                   EXHIBIT "C"

                             Compliance Certificate

         I, the President of ULTRA RESOURCES, INC. (the "Company"), pursuant to
Section 5.05 of the First Amended and Restated Credit Agreement dated as of
March 1, 2002, by and among the Company, BANK ONE, NA, as Administrative Agent,
a Bank and the LC Issuer, and the other Banks that become party thereto (the
"Agreement") do hereby certify, as of the date hereof, that to my knowledge:

         (a) No Event of Default (as defined in the Agreement) or Unmatured
             Event Of Default (as defined in the Agreement) has occurred and is
             continuing except for the following events (include actions taken
             to cure such situations):

             ___________________________________________________________________
             ___________________________________________________________________
             ___________________________________________________________________
             ___________________________________________________________________
             ___________________________________________________________________
             ___________________________________________________________________

         (b) No Material Adverse Change has occurred since the effective date of
             the latest audited consolidated Financial Statements of the Company
             delivered to the Administrative Agent;

         (c) Except as otherwise stated in the Schedule, if any, attached
             hereto, each of the representations and warranties of the Company
             contained in Article IV of the Agreement is true and correct in all
             respects [include on the attached Schedule, if any, any
             qualifications to the representations in Section 4.07 of the
             Agreement that have occurred since the date of the last Compliance
             Certificate]; and

         (d) The Company's consolidated financial condition for the quarter
             ending is__________ as follows:

                                        9
<PAGE>

<TABLE>
<CAPTION>
                                             DATE OR                                                               ACTUAL
                                              TIME                       REQUIRED RATIO OR                        RATIO OR
      FINANCIAL COVENANT                     PERIOD                           AMOUNT                               AMOUNT
      ------------------                     ------                           ------                               ------
<S>                                          <C>             <C>                                                   <C>
(a) Consolidated Tangible                    Term of         not < $80,000,000.00 plus 75% of Ultra                _______
    Net Worth                                Loan            Petroleum Corp.'s (as defined in the
                                                             Agreement) positive consolidated Net Income,
                                                             if any, accrued during each calendar quarter
                                                             subsequent to 9/30/01, calculated
                                                             cumulatively as of the end of each fiscal
                                                             quarter of Ultra Petroleum Corp. beginning
                                                             with the quarter ending 12/31/01, with no
                                                             reduction for negative Net Income during any
                                                             such quarter, plus 100% of any increase in
                                                             Stockholder's Equity resulting from the sale
                                                             or issuance of stock in Ultra Petroleum
                                                             Corp. or any of its Subsidiaries subsequent
                                                             to 12/31/01.

(b) Current Ratio for any                    Term of         not < 1.00 to 1.00, calculated based on               _______
    fiscal quarter                           Loan            both: (a) the Consolidated Financial
                                                             Statements (as defined in the Agreement),
                                                             and (b) the consolidating financial
                                                             statements applicable to Borrower, which
                                                             form a part of the Consolidated Financial
                                                             Statements.

(c) Ratio of EBITDA to                       Term of         not < 3.50 to 1.00, calculated on a rolling           _______
    interest expense on all                  Loan            four (4) quarter basis and based on both:
    Indebtedness as of the                                   (a) the Consolidated Financial Statements,
    end of each fiscal                                       and (b) the consolidating financial
    quarter                                                  statements applicable to Borrower, which
                                                             form a part of the Consolidated Financial
                                                             Statements.

(d) Intercompany Transfers                   During          not > $25,000,00.00, without the prior                _______
    to Sino-American                         calendar year   written approval of the Required
    Energy Corporation                       2003            Banks
</TABLE>

                                       10
<PAGE>

<TABLE>
<CAPTION>
                                             DATE OR                                                               ACTUAL
                                              TIME                     REQUIRED RATIO OR                          RATIO OR
      FINANCIAL COVENANT                     PERIOD                        AMOUNT                                  AMOUNT
      ------------------                     ------                         ------                                 ------
<S>                                          <C>             <C>                                                   <C>
(e) Intercompany Transfers                   During each     not > $35,000,000.00, without the                     _______
    to Sino-American                         calendar year   prior written approval of the Required
    Energy Corporation                       beginning       Banks
                                             with calendar
                                             year 2004
</TABLE>

This certificate is executed this_____ day of________,_______.

                                             ULTRA RESOURCES, INC.

                                             By:_______________________________.
                                                _______________________________
                                                President and CEO

                                       11

<PAGE>

                                 REVOLVING NOTE

$27,419,354.84                   Houston, Texas                      May 14,2003

         On the dates hereinafter prescribed, for value received, ULTRA
RESOURCES, INC., a Wyoming corporation, (herein called "Borrower"), having an
address at 16801 Greenspoint Park, Suite 370, Houston, Texas 77060, promises to
pay to the order of BANK OF SCOTLAND. (herein called "Bank"), at its principal
offices at 565 Fifth Avenue, New York, New York 10017, (i) the principal amount
of TWENTY-SEVEN MILLION, FOUR HUNDRED NINETEEN THOUSAND, THREE HUNDRED
FIFTY-FOUR AND 84/100 US DOLLARS ($27,419,354.84) or the principal amount
advanced pursuant to the terms of the Credit Agreement (defined herein) as of
the date of maturity hereof, whether by acceleration or otherwise, whichever may
be the lesser, and (ii) interest on the principal balance from time to time
advanced and remaining unpaid from the date of the advance until maturity at a
rate of interest equal to lesser of (a) the "Floating Rate" (as defined and
calculated in the Credit Agreement), or (b) the Maximum Rate (as defined and
calculated in the Credit Agreement). Any increase or decrease in interest rate
resulting from a change in the Maximum Rate shall be effective immediately when
such change becomes effective, without notice to the Borrower, unless Applicable
Law (as defined in the Credit Agreement) requires that such increase or decrease
not be effective until a later time, in which event such increase or decrease
shall be effective at the earliest time permitted under the provisions of such
law.

         Notwithstanding the foregoing, if during any period the Floating Rate
exceeds the Maximum Rate, the rate of interest in effect on this Note shall be
limited to the Maximum Rate during each such period, but at all times thereafter
the rate of interest in effect on this Note shall be the Maximum Rate or, if
there is no Maximum Rate, the Agreed Maximum Rate (as defined below), until the
total amount of interest accrued on this Note equals the total amount of
interest which would have accrued hereon if the Floating Rate had at all times
been in effect.

         This Note is a revolving credit note and it is contemplated that by
reason of prepayments hereon there may be times when no indebtedness is owing
hereunder; but notwithstanding such occurrence, this Note shall remain valid and
in full force and effect as to each principal advance made hereunder subsequent
to each such occurrence. Each principal advance and each payment hereof made
pursuant to this Note shall be reflected by the Bank's records and the aggregate
unpaid amounts reflected by such records shall constitute rebuttably presumptive
evidence of the principal and unpaid, accrued interest remaining outstanding on
this Note.

         "Agreed Maximum Rate" means a per annum rate of seven and three-fourths
percent (7.75%) plus the Floating Rate from time to time in effect, which Agreed
Maximum Rate shall apply only during any period while there is no Maximum Rate
applicable to this Note.

         Other capitalized terms used herein, that are not defined herein, shall
have the meanings prescribed therefor in the Credit Agreement.

         The Borrower and the Bank hereby agree that Chapter 346 of the Texas
Finance Code, shall not apply to this Note or the loan transaction evidenced by,
and referenced in, the Credit Agreement (hereinafter defined) in any manner,
including without limitation, to any account or arrangement evidenced or created
by, or provided for in, this Note.

                                                                    MDW
                                                             -------------------
                                                             Borrower's Initials

                                       1

<PAGE>

         The principal sum of this Note, after giving credit for unadvanced
principal, if any, remaining at final maturity, shall be due and payable on or
before March 1, 2006; interest to accrue upon the principal sum from time to
time owing and unpaid hereunder shall be due and payable as provided in the
Credit Agreement; provided, however, the final installment of interest hereunder
shall be due and payable not later than the maturity of the principal sum
hereof, howsoever such maturity may be brought about.

         In no event shall the aggregate of the interest on this Note, plus any
other amounts paid in connection with the loan evidenced by this Note which
would under Applicable Law be deemed "interest," ever exceed the maximum amount
of interest which, under Applicable Law, could be lawfully charged on this Note.
The Bank and the Borrower specifically intend and agree to limit contractually
the interest payable on this Note to not more than an amount determined at the
Maximum Rate. Therefore, none of the terms of this Note or any other instruments
pertaining to or securing this Note shall ever be construed to create a contract
to pay interest at a rate in excess of the Maximum Rate, and neither the
Borrower nor any other party liable herefor shall ever be liable for interest in
excess of that determined at the Maximum Rate, and the provisions of this
paragraph shall control over all provisions of this Note or of any other
instruments pertaining to or securing this Note. If any amount of interest taken
or received by the Bank shall be in excess of the maximum amount of interest
which, under Applicable Law, could lawfully have been collected on this Note,
then the excess shall be deemed to have been the result of a mathematical error
by the parties hereto and shall be refunded promptly to the Borrower. All
amounts paid or agreed to be paid in connection with the indebtedness evidenced
by this Note which would under Applicable Law be deemed "interest" shall, to the
extent permitted by Applicable Law, be amortized, prorated, allocated and spread
throughout the full term of this Note.

         This Note is secured by all security agreements, collateral
assignments, mortgages and lien instruments executed by the Borrower (or by any
other party) in favor of Bank One, NA, as Administrative Agent for the Banks,
including those executed simultaneously herewith, those executed heretofore, and
those hereafter executed, and including specifically and without limitation the
Security Instruments described and defined in that certain Credit Agreement
dated as of March 22, 2000 by and between Borrower, Ultra Petroleum (USA) Inc.,
and Bank One, Texas, National Association, as amended by that certain First
Amendment to Credit Agreement dated as of July 19, 2001 by and between Borrower
and Bank One, NA, and as amended and restated by that certain First Amended and
Restated Credit Agreement dated March 1, 2002, as amended by the First Amendment
thereto dated November 4,2002 and the Second Amendment thereto dated May 14,
2003, by and among Borrower, Bank One, NA, as the Administrative Agent, as a
Bank and as LC Issuer, and the several other banks and financial institutions
who are from time to time party thereto as Banks (as may be further amended from
time to time, the "Credit Agreement").

         This Note is a Note issued pursuant to the Credit Agreement. Reference
is hereby made to the Credit Agreement for a statement of the rights and
obligations of the holder of this Note and the duties and obligations of the
Borrower in relation thereto; but neither this reference to the Credit Agreement
nor any provisions thereof shall affect or impair the absolute and unconditional
obligation of the Borrower to pay any outstanding and unpaid principal of and
interest on this Note when due, in accordance with the terms of the Credit
Agreement. Each
                                                                    MDW
                                                             -------------------
                                                             Borrower's Initials

                                       2

<PAGE>

advance and each payment made pursuant to this Note shall be reflected by
notations made by the Bank on its records and the aggregate unpaid amounts
reflected by the notations on the records of the Bank shall be deemed rebuttably
presumptive evidence of the principal amount owing under this Note.

         In the event of default in the payment when due of any of the principal
of or any interest on this Note, or in the event of default under the terms of
the Credit Agreement or any of the Security Instruments, or if any event occurs
or condition exists which authorizes the acceleration of the maturity of this
Note under any agreement made by the Borrower, the Bank (or other holder of this
Note) may, at its option, without presentment or demand or any notice to the
Borrower or any other person liable herefor, declare the unpaid principal
balance of and accrued interest on this Note to be immediately due and payable.

         If this Note is collected by suit or through the Probate or Bankruptcy
Court, or any judicial proceeding, or if this Note is not paid at maturity,
however such maturity may be brought about, and is placed in the hands of an
attorney for collection, then the Borrower agrees to pay reasonable and
documented attorneys' fees, not to exceed 10% of the full amount of principal
and interest owing hereon at the time this Note is placed in the hands of an
attorney.

         The Borrower and all sureties, endorsers and guarantors of this Note
waive demand, presentment for payment, notice of nonpayment, protest, notice of
protest, notice of intent to accelerate maturity, notice of acceleration of
maturity, and all other notices, filing of suit and diligence in collecting this
Note or enforcing any of the security herefor, and agree to any substitution,
exchange or release of any such security or the release of any party primarily
or secondarily liable hereon and further agrees that it will not be necessary
for the Bank, in order to enforce payment of this Note by them, to first
institute suit or exhaust its remedies against any Borrower or others liable
herefor, or to enforce its rights against any security herefor, and consent to
any one or more extensions or postponements of time of payment of this Note on
any terms or any other indulgences with respect hereto, without notice thereof
to any of them. The Bank may transfer this Note, and the rights and privileges
of the Bank under this Note shall inure to the benefit of the Bank's
representatives, successors or assigns as set forth in the Credit Agreement.

         This Note partially amends and restates the following: (i) that certain
Amended and Restated Revolving Note dated March 1, 2002 in the original
principal amount of $40,000,000 executed by Borrower and payable to the order of
Bank One, NA, (ii) that certain Amended and Restated Revolving Note dated March
1, 2002 in the original principal amount of $2 1,250,000 executed by Borrower
and payable to the order of Hibernia National Bank, (iii) that certain Amended
and Restated Revolving Note dated March 1, 2002 in the original principal amount
of $37,500,000 executed by Borrower and payable to the order of Guaranty Bank,
FSB, (iv) that certain Amended and Restated Revolving Note dated March 1, 2002
in the original principal amount of $13,750,000 executed by Borrower and payable
to the order of Compass Bank, and (v) that certain Amended and Restated
Revolving Note dated March 1, 2002 in the original principal amount of
$37,500,000 executed by Borrower and payable to the order of Union Bank of
California, N.A.

                                                                    MDW
                                                             -------------------
                                                             Borrower's Initials

                                       3

<PAGE>

         Executed as of the date and year first set forth above.

                                       ULTRA RESOURCES, INC.
ATTEST:

/s/ Charlotte H. Kauffman              By: /s/ Michael D. Watford
-----------------------------              ------------------------------
Charlotte H. Kauffman                      Michael D. Watford
Secretary                                  President and Chief Executive Officer

                                        4

<PAGE>

                   SECOND AMENDED AND RESTATED REVOLVING NOTE

 $54,838,709.68           Houston, Texas                    March 1, 2002

         On the dates hereinafter prescribed, for value received, ULTRA
RESOURCES, INC., a Wyoming corporation, (herein called "Borrower"), having an
address at 16801 Greenspoint Park, Suite 370, Houston, Texas 77060, promises to
pay to the order of BANK ONE, NA (herein called "Bank"), at its principal
offices at 910 Travis, 6th Floor, Houston, Texas 77002, (i) the principal amount
of U.S. FIFTY-FOUR MILLION, EIGHT HUNDRED THIRTY-EIGHT THOUSAND, SEVEN HUNDRED
NINE AND 68/100 DOLLARS ($54,838,709.68) or the principal amount advanced
pursuant to the terms of the Credit Agreement (defined herein) as of the date of
maturity hereof, whether by acceleration or otherwise, whichever may be the
lesser, and (ii) interest on the principal balance from time to time advanced
and remaining unpaid from the date of the advance until maturity at a rate of
interest equal to lesser of (a) the "Floating Rate" (as defined and calculated
in the Credit Agreement), or (b) the Maximum Rate (as defined and calculated in
the Credit Agreement). Any increase or decrease in interest rate resulting from
a change in the Maximum Rate shall be effective immediately when such change
becomes effective, without notice to the Borrower, unless Applicable Law (as
defined in the Credit Agreement) requires that such increase or decrease not be
effective until a later time, in which event such increase or decrease shall be
effective at the earliest time permitted under the provisions of such law.

         Notwithstanding the foregoing, if during any period the Floating Rate
exceeds the Maximum Rate, the rate of interest in effect on this Note shall be
limited to the Maximum Rate during each such period, but at all times thereafter
the rate of interest in effect on this Note shall be the Maximum Rate or, if
there is no Maximum Rate, the Agreed Maximum Rate (as defined below), until the
total amount of interest accrued on this Note equals the total amount of
interest which would have accrued hereon if the Floating Rate had at all times
been in effect.

         This Note is a revolving credit note and it is contemplated that by
reason of prepayments hereon there may be times when no indebtedness is owing
hereunder; but notwithstanding such occurrence, this Note shall remain valid and
in full force and effect as to each principal advance made hereunder subsequent
to each such occurrence. Each principal advance and each payment hereof made
pursuant to this Note shall be reflected by the Bank's records and the aggregate
unpaid amounts reflected by such records shall constitute rebuttably presumptive
evidence of the principal and unpaid, accrued interest remaining outstanding on
this Note.

         "Agreed Maximum Rate" means a per annum rate of seven and
three-fourths percent (7.75%) plus the Floating Rate from time to time in
effect, which Agreed Maximum Rate shall apply only during any period while there
is no Maximum Rate applicable to this Note.

         Other capitalized terms used herein, that are not defined herein, shall
have the meanings prescribed therefor in the Credit Agreement.

                                                                     MDW
                                                             -------------------
                                                             Borrower's Initials

<PAGE>

         The Borrower and the Bank hereby agree that Chapter 346 of the Texas
Finance Code, shall not apply to this Note or the loan transaction evidenced by,
and referenced in, the Credit Agreement (hereinafter defined) in any manner,
including without limitation, to any account or arrangement evidenced or created
by, or provided for in, this Note.

         The principal sum of this Note, after giving credit for unadvanced
principal, if any, remaining at final maturity, shall be due and payable on or
before March 1, 2006; interest to accrue upon the principal sum from time to
time owing and unpaid hereunder shall be due and payable as provided in the
Credit Agreement; provided, however, the final installment of interest hereunder
shall be due and payable not later than the maturity of the principal sum
hereof, howsoever such maturity may be brought about.

         In no event shall the aggregate of the interest on this Note, plus any
other amounts paid in connection with the loan evidenced by this Note which
would under Applicable Law be deemed "interest," ever exceed the maximum amount
of interest which, under Applicable Law, could be lawfully charged on this Note.
The Bank and the Borrower specifically intend and agree to limit contractually
the interest payable on this Note to not more than an amount determined at the
Maximum Rate. Therefore, none of the terms of this Note or any other instruments
pertaining to or securing this Note shall ever be construed to create a contract
to pay interest at a rate in excess of the Maximum Rate, and neither the
Borrower nor any other party liable herefor shall ever be liable for interest in
excess of that determined at the Maximum Rate, and the provisions of this
paragraph shall control over all provisions of this Note or of any other
instruments pertaining to or securing this Note. If any amount of interest taken
or received by the Bank shall be in excess of the maximum amount of interest
which, under Applicable Law, could lawfully have been collected on this Note,
then the excess shall be deemed to have been the result of a mathematical error
by the parties hereto and shall be refunded promptly to the Borrower. All
amounts paid or agreed to be paid in connection with the indebtedness evidenced
by this Note which would under Applicable Law be deemed "interest" shall, to the
extent permitted by Applicable Law, be amortized, prorated, allocated and spread
throughout the full term of this Note.

         This Note is secured by all security agreements, collateral
assignments, mortgages and lien instruments executed by the Borrower (or by any
other party) in favor of Bank One, NA, as Administrative Agent for the Banks,
including those executed simultaneously herewith, those executed heretofore and
those hereafter executed, and including specifically and without limitation the
Security Instruments described and defined in that certain Credit Agreement
dated as of March 22, 2000 by and between Borrower, Ultra Petroleum (USA) Inc.,
and Bank One, Texas, National Association, as amended by that certain First
Amendment to Credit Agreement dated as of July 19, 2001 by and between Borrower
and Bank One, NA, and as amended and restated by that certain First Amended and
Restated Credit Agreement dated March 1, 2002, as amended by the First Amendment
thereto dated November 4, 2002 and the Second Amendment thereto dated May 14,
2003, by and among Borrower, Bank One, NA, as the Administrative Agent, as a
Bank and as LC Issuer, and the several other banks and financial institutions
who are from time to time party thereto as Banks (as may be further amended from
time to time, the "Credit Agreement").

                                                                     MDW
                                                             -------------------
                                                             Borrower's Initials

                                       2

<PAGE>

         This Note is the Revolving Note issued pursuant to the Credit
Agreement. Reference is hereby made to the Credit Agreement for a statement of
the rights and obligations of the holder of this Note and the duties and
obligations of the Borrower in relation thereto; but neither this reference to
the Credit Agreement nor any provisions thereof shall affect or impair the
absolute and unconditional obligation of the Borrower to pay any outstanding and
unpaid principal of and interest on this Note when due, in accordance with the
terms of the Credit Agreement. Each advance and each payment made pursuant to
this Note shall be reflected by notations made by the Bank on its records and
the aggregate unpaid amounts reflected by the notations on the records of the
Bank shall be deemed rebuttably presumptive evidence of the principal amount
owing under this Note.

         In the event of default in the payment when due of any of the principal
of or any interest on this Note, or in the event of default under the terms of
the Credit Agreement or any of the Security Instruments, or if any event occurs
or condition exists which authorizes the acceleration of the maturity of this
Note under any agreement made by the Borrower, the Bank (or other holder of this
Note) may, at its option, without presentment or demand or any notice to the
Borrower or any other person liable herefor, declare the unpaid principal
balance of and accrued interest on this Note to be immediately due and payable.

         If this Note is collected by suit or through the Probate or Bankruptcy
Court, or any judicial proceeding, or if this Note is not paid at maturity,
however such maturity may be brought about, and is placed in the hands of an
attorney for collection, then the Borrower agrees to pay reasonable and
documented attorneys' fees, not to exceed 10% of the full amount of principal
and interest owing hereon at the time this Note is placed in the hands of an
attorney.

         The Borrower and all sureties, endorsers and guarantors of this Note
waive demand, presentment for payment, notice of nonpayment, protest, notice of
protest, notice of intent to accelerate maturity, notice of acceleration of
maturity, and all other notices, filing of suit and diligence in collecting this
Note or enforcing any of the security herefor, and agree to any substitution,
exchange or release of any such security or the release of any party primarily
or secondarily liable hereon and further agrees that it will not be necessary
for the Bank, in order to enforce payment of this Note by them, to first
institute suit or exhaust its remedies against any Borrower or others liable
herefor, or to enforce its rights against any security herefor, and consent to
any one or more extensions or postponements of time of payment of this Note on
any terms or any other indulgences with respect hereto, without notice thereof
to any of them. The Bank may transfer this Note, and the rights and privileges
of the Bank under this Note shall inure to the benefit of the Bank's
representatives, successors or assigns.

         This Note amends and restates that certain Amended and Restated
Revolving Note dated March 1, 2002 in the original principal amount of
$40,000,000 executed by ULTRA RESOURCES, INC. and payable to the order of Bank
One, NA (the "Prior Note"). All liens and security interests that exist to
secure the indebtedness evidenced by that Prior Note shall continue in force and
effect to secure the indebtedness evidenced by this Note.

                                                                     MDW
                                                             -------------------
                                                             Borrower's Initials

                                       3

<PAGE>

         Executed as of May 14,2003, but effective as of the date and year first
set forth above.

                                                    ULTRA RESOURCES, INC.

Attest:

/s/ Charlotte H. Kauffman              By: /s/ Michael D. Watford
-------------------------                  ---------------------------
    Charlotte H. Kauffman                  Michael D. Watford
    Secretary                              President and Chief Executive Officer

                                        4

<PAGE>

                    SECOND AMENDED AND RESTATED REVOLVING NOTE

$54,838,709.68                   Houston, Texas                    March 1, 2002

         On the dates hereinafter prescribed, for value received, ULTRA
RESOURCES, INC., a Wyoming corporation, (herein called "Borrower"), having an
address at 16801 Greenspoint Park, Suite 370, Houston, Texas 77060, promises to
pay to the order of GUARANTY BANK, FSB (herein called "Bank"), at its principal
offices at 333 Clay Street, Suite 4430, Houston, Texas 77002, (i) the principal
amount of U.S. FIFTY-FOUR MILLION, EIGHT HUNDRED THIRTY-EIGHT THOUSAND, SEVEN
HUNDRED NINE AND 68/100 DOLLARS ($54,838,709.68) or the principal amount
advanced pursuant to the terms of the Credit Agreement (defined herein) as of
the date of maturity hereof, whether by acceleration or otherwise, whichever may
be the lesser, and (ii) interest on the principal balance from time to time
advanced and remaining unpaid from the date of the advance until maturity at a
rate of interest equal to lesser of (a) the "Floating Rate" (as defined and
calculated in the Credit Agreement), or (b) the Maximum Rate (as defined and
calculated in the Credit Agreement). Any increase or decrease in interest rate
resulting from a change in the Maximum Rate shall be effective immediately when
such change becomes effective, without notice to the Borrower, unless Applicable
Law (as defined in the Credit Agreement) requires that such increase or decrease
not be effective until a later time, in which event such increase or decrease
shall be effective at the earliest time permitted under the provisions of such
law.

         Notwithstanding the foregoing, if during any period the Floating Rate
exceeds the Maximum Rate, the rate of interest in effect on this Note shall be
limited to the Maximum Rate during each such period, but at all times thereafter
the rate of interest in effect on this Note shall be the Maximum Rate or, if
there is no Maximum Rate, the Agreed Maximum Rate (as defined below), until the
total amount of interest accrued on this Note equals the total amount of
interest which would have accrued hereon if the Floating Rate had at all times
been in effect.

         This Note is a revolving credit note and it is contemplated that by
reason of prepayments hereon there may be times when no indebtedness is owing
hereunder; but notwithstanding such occurrence, this Note shall remain valid and
in full force and effect as to each principal advance made hereunder subsequent
to each such occurrence. Each principal advance and each payment hereof made
pursuant to this Note shall be reflected by the Bank's records and the aggregate
unpaid amounts reflected by such records shall constitute rebuttably presumptive
evidence of the principal and unpaid, accrued interest remaining outstanding on
this Note.

         "Agreed Maximum Rate" means a per annum rate of seven and three-fourths
percent (7.75%) plus the Floating Rate from time to time in effect, which Agreed
Maximum Rate shall apply only during any period while there is no Maximum Rate
applicable to this Note.

         Other capitalized terms used herein, that are not defined herein, shall
have the meanings prescribed therefor in the Credit Agreement.

                                                                     MDW
                                                             -------------------
                                                             Borrower's Initials

<PAGE>

         The Borrower and the Bank hereby agree that Chapter 346 of the Texas
Finance Code, shall not apply to this Note or the loan transaction evidenced by,
and referenced in, the Credit Agreement (hereinafter defined) in any manner,
including without limitation, to any account or arrangement evidenced or created
by, or provided for in, this Note.

         The principal sum of this Note, after giving credit for unadvanced
principal, if any, remaining at final maturity, shall be due and payable on or
before March 1, 2006; interest to accrue upon the principal sum from time to
time owing and unpaid hereunder shall be due and payable as provided in the
Credit Agreement; provided, however, the final installment of interest hereunder
shall be due and payable not later than the maturity of the principal sum
hereof, howsoever such maturity may be brought about.

         In no event shall the aggregate of the interest on this Note, plus any
other amounts paid in connection with the loan evidenced by this Note which
would under Applicable Law be deemed "interest," ever exceed the maximum amount
of interest which, under Applicable Law, could be lawfully charged on this Note.
The Bank and the Borrower specifically intend and agree to limit contractually
the interest payable on this Note to not more than an amount determined at the
Maximum Rate. Therefore, none of the terms of this Note or any other instruments
pertaining to or securing this Note shall ever be construed to create a contract
to pay interest at a rate in excess of the Maximum Rate, and neither the
Borrower nor any other party liable herefor shall ever be liable for interest in
excess of that determined at the Maximum Rate, and the provisions of this
paragraph shall control over all provisions of this Note or of any other
instruments pertaining to or securing this Note. If any amount of interest taken
or received by the Bank shall be in excess of the maximum amount of interest
which, under Applicable Law, could lawfully have been collected on this Note,
then the excess shall be deemed to have been the result of a mathematical error
by the parties hereto and shall be refunded promptly to the Borrower. All
amounts paid or agreed to be paid in connection with the indebtedness evidenced
by this Note which would under Applicable Law be deemed "interest" shall, to the
extent permitted by Applicable Law, be amortized, prorated, allocated and spread
throughout the full term of this Note.

         This Note is secured by all security agreements, collateral
assignments, mortgages and lien instruments executed by the Borrower (or by any
other party) in favor of Bank One, NA, as Administrative Agent for the Banks,
including those executed simultaneously herewith, those executed heretofore and
those hereafter executed, and including specifically and without limitation the
Security Instruments described and defined in that certain Credit Agreement
dated as of March 22, 2000 by and between Borrower, Ultra Petroleum (USA) Inc.,
and Bank One, Texas, National Association, as amended by that certain First
Amendment to Credit Agreement dated as of July 19, 2001 by and between Borrower
and Bank One, NA, and as amended and restated by that certain First Amended and
Restated Credit Agreement dated March 1, 2002, as amended by the First
Amendment thereto dated November 4, 2002, and the Second Amendment thereto dated
May 14, 2003, by and among Borrower, Bank One, NA, as the Administrative Agent,
as a Bank and as LC Issuer, and the several other banks and financial
institutions who are from time to time party thereto as Banks (as may be further
amended from time to time, the "Credit Agreement").

                                                                     MDW
                                                             -------------------
                                                             Borrower's Initials

                                       2

<PAGE>

         This Note is the Revolving Note issued pursuant to the Credit
Agreement. Reference is hereby made to the Credit Agreement for a statement of
the rights and obligations of the holder of this Note and the duties and
obligations of the Borrower in relation thereto; but neither this reference to
the Credit Agreement nor any provisions thereof shall affect or impair the
absolute and unconditional obligation of the Borrower to pay any outstanding and
unpaid principal of and interest on this Note when due, in accordance with the
terms of the Credit Agreement. Each advance and each payment made pursuant to
this Note shall be reflected by notations made by the Bank on its records and
the aggregate unpaid amounts reflected by the notations on the records of the
Bank shall be deemed rebuttably presumptive evidence of the principal amount
owing under this Note.

         In the event of default in the payment when due of any of the principal
of or any interest on this Note, or in the event of default under the terms of
the Credit Agreement or any of the Security Instruments, or if any event occurs
or condition exists which authorizes the acceleration of the maturity of this
Note under any agreement made by the Borrower, the Bank (or other holder of this
Note) may, at its option, without presentment or demand or any notice to the
Borrower or any other person liable herefor, declare the unpaid principal
balance of and accrued interest on this Note to be immediately due and payable.

         If this Note is collected by suit or through the Probate or Bankruptcy
Court, or any judicial proceeding, or if this Note is not paid at maturity,
however such maturity may be brought about, and is placed in the hands of an
attorney for collection, then the Borrower agrees to pay reasonable and
documented attorneys' fees, not to exceed 10% of the full amount of principal
and interest owing hereon at the time this Note is placed in the hands of an
attorney.

         The Borrower and all sureties, endorsers and guarantors of this Note
waive demand, presentment for payment, notice of nonpayment, protest, notice of
protest, notice of intent to accelerate maturity, notice of acceleration of
maturity, and all other notices, filing of suit and diligence in collecting this
Note or enforcing any of the security herefor, and agree to any substitution,
exchange or release of any such security or the release of any party primarily
or secondarily liable hereon and further agrees that it will not be necessary
for the Bank, in order to enforce payment of this Note by them, to first
institute suit or exhaust its remedies against any Borrower or others liable
herefor, or to enforce its rights against any security herefor, and consent to
any one or more extensions or postponements of time of payment of this Note on
any terms or any other indulgences with respect hereto, without notice thereof
to any of them. The Bank may transfer this Note, and the rights and privileges
of the Bank under this Note shall inure to the benefit of the Bank's
representatives, successors or assigns.

         This Note amends and restates that certain Amended and Restated
Reducing Revolving Note dated March 1, 2002 in the original principal amount of
$37,500,000 executed by ULTRA RESOURCES, INC. and payable to the order of Bank
One, NA (the "Prior Note"). All liens and security interests that exist to
secure the indebtedness evidenced by that Prior Note shall continue in force and
effect to secure the indebtedness evidenced by this Note.

                                                                     MDW
                                                             -------------------
                                                             Borrower's Initials

                                       3

<PAGE>

         Executed as of May 14,2003, but effective as of the date and year first
set forth above.

                                   ULTRA RESOURCES, INC.

Attest:

/s/ Charlotte H. Kauffman          By: /s/ Michael D. Watford
-------------------------              -----------------------------------------
Charlotte H. Kauffman                  Michael D. Watford
Secretary                              President and Chief Executive Officer

                                       4

<PAGE>

                   SECOND AMENDED AND RESTATED REVOLVING NOTE

$54,838,709.68                   Houston, Texas                    March 1, 2002

         On the dates hereinafter prescribed, for value received, ULTRA
RESOURCES, INC., a Wyoming corporation, (herein called "Borrower"), having an
address at 16801 Greenspoint Park, Suite 370, Houston, Texas 77060, promises to
pay to the order of UNION BANK OF CALIFORNIA, N.A. (herein called "Bank"), at
its principal offices at 500 North Akard, Suite 4200, Dallas, Texas 75201, (i)
the principal amount of U.S. FIFTY-FOUR MILLION, EIGHT HUNDRED THIRTY-EIGHT
THOUSAND, SEVEN HUNDRED NINE AND 68/100 DOLLARS ($54,838,709.68) or the
principal amount advanced pursuant to the terms of the Credit Agreement (defined
herein) as of the date of maturity hereof, whether by acceleration or otherwise,
whichever may be the lesser, and (ii) interest on the principal balance from
time to time advanced and remaining unpaid from the date of the advance until
maturity at a rate of interest equal to lesser of (a) the "Floating Rate" (as
defined and calculated in the Credit Agreement), or (b) the Maximum Rate (as
defined and calculated in the Credit Agreement). Any increase or decrease in
interest rate resulting from a change in the Maximum Rate shall be effective
immediately when such change becomes effective, without notice to the Borrower,
unless Applicable Law (as defined in the Credit Agreement) requires that such
increase or decrease not be effective until a later time, in which event such
increase or decrease shall be effective at the earliest time permitted under the
provisions of such law.

         Notwithstanding the foregoing, if during any period the Floating Rate
exceeds the Maximum Rate, the rate of interest in effect on this Note shall be
limited to the Maximum Rate during each such period, but at all times thereafter
the rate of interest in effect on this Note shall be the Maximum Rate or, if
there is no Maximum Rate, the Agreed Maximum Rate (as defined below), until the
total amount of interest accrued on this Note equals the total amount of
interest which would have accrued hereon if the Floating Rate had at all times
been in effect.

         This Note is a revolving credit note and it is contemplated that by
reason of prepayments hereon there may be times when no indebtedness is owing
hereunder; but notwithstanding such occurrence, this Note shall remain valid and
in full force and effect as to each principal advance made hereunder subsequent
to each such occurrence. Each principal advance and each payment hereof made
pursuant to this Note shall be reflected by the Bank's records and the aggregate
unpaid amounts reflected by such records shall constitute rebuttably presumptive
evidence of the principal and unpaid, accrued interest remaining outstanding on
this Note.

         "Agreed Maximum Rate" means a per annum rate of seven and three-fourths
percent (7.75%) plus the Floating Rate from time to time in effect, which Agreed
Maximum Rate shall apply only during any period while there is no Maximum Rate
applicable to this Note.

         Other capitalized terms used herein, that are not defined herein, shall
have the meanings prescribed therefor in the Credit Agreement.

         The Borrower and the Bank hereby agree that Chapter 346 of the Texas
Finance Code, shall not apply to this Note or the loan transaction evidenced by,
and referenced in, the Credit

                                                                     MDW
                                                             -------------------
                                                             Borrower's Initials

                                       1

<PAGE>

Agreement (hereinafter defined) in any manner, including without limitation, to
any account or arrangement evidenced or created by, or provided for in, this
Note.

         The principal sum of this Note, after giving credit for unadvanced
principal, if any, remaining at final maturity, shall be due and payable on or
before March 1, 2006; interest to accrue upon the principal sum from time to
time owing and unpaid hereunder shall be due and payable as provided in the
Credit Agreement; provided, however, the final installment of interest hereunder
shall be due and payable not later than the maturity of the principal sum
hereof, howsoever such maturity may be brought about.

         In no event shall the aggregate of the interest on this Note, plus any
other amounts paid in connection with the loan evidenced by this Note which
would under Applicable Law be deemed "interest," ever exceed the maximum amount
of interest which, under Applicable Law, could be lawfully charged on this Note.
The Bank and the Borrower specifically intend and agree to limit contractually
the interest payable on this Note to not more than an amount determined at the
Maximum Rate. Therefore, none of the terms of this Note or any other instruments
pertaining to or securing this Note shall ever be construed to create a contract
to pay interest at a rate in excess of the Maximum Rate, and neither the
Borrower nor any other party liable herefor shall ever be liable for interest in
excess of that determined at the Maximum Rate, and the provisions of this
paragraph shall control over all provisions of this Note or of any other
instruments pertaining to or securing this Note. If any amount of interest taken
or received by the Bank shall be in excess of the maximum amount of interest
which, under Applicable Law, could lawfully have been collected on this Note,
then the excess shall be deemed to have been the result of a mathematical error
by the parties hereto and shall be refunded promptly to the Borrower. All
amounts paid or agreed to be paid in connection with the indebtedness evidenced
by this Note which would under Applicable Law be deemed "interest" shall, to the
extent permitted by Applicable Law, be amortized, prorated, allocated and spread
throughout the full term of this Note.

         This Note is secured by all security agreements, collateral
assignments, mortgages and lien instruments executed by the Borrower (or by any
other party) in favor of Bank One, NA, as Administrative Agent for the Banks,
including those executed simultaneously herewith, those executed heretofore and
those hereafter executed, and including specifically and without limitation the
Security Instruments described and defined in that certain Credit Agreement
dated as of March 22, 2000 by and between Borrower, Ultra Petroleum (USA) Inc.,
and Bank One, Texas, National Association, as amended by that certain First
Amendment to Credit Agreement dated as of July 19, 2001 by and between Borrower
and Bank One, NA, and as amended and restated by that certain First Amended and
Restated Credit Agreement dated March 1, 2002, as amended by the First Amendment
thereto dated November 4, 2002 and the Second Amendment thereto dated May 14,
2003 by and among Borrower, Bank One, NA, as the Administrative Agent, as a Bank
and as LC Issuer, and the several other banks and financial institutions who are
from time to time party thereto as Banks (as may be further amended from time to
time, the "Credit Agreement").

         This Note is the Revolving Note issued pursuant to the Credit
Agreement. Reference is hereby made to the Credit Agreement for a statement of
the rights and obligations of the holder of this Note and the duties and
obligations of the Borrower in relation thereto; but neither this

                                                                     MDW
                                                             -------------------
                                                             Borrower's Initials

                                       2

<PAGE>

reference to the Credit Agreement nor any provisions thereof shall affect or
impair the absolute and unconditional obligation of the Borrower to pay any
outstanding and unpaid principal of and interest on this Note when due, in
accordance with the terms of the Credit Agreement. Each advance and each payment
made pursuant to this Note shall be reflected by notations made by the Bank on
its records and the aggregate unpaid amounts reflected by the notations on the
records of the Bank shall be deemed rebuttably presumptive evidence of the
principal amount owing under this Note.

         In the event of default in the payment when due of any of the principal
of or any interest on this Note, or in the event of default under the terms of
the Credit Agreement or any of the Security Instruments, or if any event occurs
or condition exists which authorizes the acceleration of the maturity of this
Note under any agreement made by the Borrower, the Bank (or other holder of this
Note) may, at its option, without presentment or demand or any notice to the
Borrower or any other person liable herefor, declare the unpaid principal
balance of and accrued interest on this Note to be immediately due and payable.

         If this Note is collected by suit or through the Probate or Bankruptcy
Court, or any judicial proceeding, or if this Note is not paid at maturity,
however such maturity may be brought about, and is placed in the hands of an
attorney for collection, then the Borrower agrees to pay reasonable and
documented attorneys' fees, not to exceed 10% of the full amount of principal
and interest owing hereon at the time this Note is placed in the hands of an
attorney.

         The Borrower and all sureties, endorsers and guarantors of this Note
waive demand, presentment for payment, notice of nonpayment, protest, notice of
protest, notice of intent to accelerate maturity, notice of acceleration of
maturity, and all other notices, filing of suit and diligence in collecting this
Note or enforcing any of the security herefor, and agree to any substitution,
exchange or release of any such security or the release of any party primarily
or secondarily liable hereon and further agrees that it will not be necessary
for the Bank, in order to enforce payment of this Note by them, to first
institute suit or exhaust its remedies against any Borrower or others liable
herefor, or to enforce its rights against any security herefor, and consent to
any one or more extensions or postponements of time of payment of this Note on
any terms or any other indulgences with respect hereto, without notice thereof
to any of them. The Bank may transfer this Note, and the rights and privileges
of the Bank under this Note shall inure to the benefit of the Bank's
representatives, successors or assigns.

         This Note amends and restates that certain Amended and Restated
Revolving Note dated March 1, 2002 in the original principal amount of
$37,500,000 executed by ULTRA RESOURCES, INC. and payable to the order of Bank
One, NA (the "Prior Note"). All liens and security interests that exist to
secure the indebtedness evidenced by that Prior Note shall continue in force and
effect to secure the indebtedness evidenced by this Note.

                                                                     MDW
                                                             -------------------
                                                             Borrower's Initials

                                       3

<PAGE>

         Executed as of May 14,2003, but effective as of the date and year first
set forth above.

                                   ULTRA RESOURCES, INC.

Attest:

/s/ Charlotte H. Kauffman          By: /s/ Michael D. Watford
-------------------------          ---------------------------------------------
    Charlotte H. Kauffman                  Michael D. Watford
    Secretary                              President and Chief Executive Officer

                                       4

<PAGE>

                   SECOND AMENDED AND RESTATED REVOLVING NOTE

$22,580,645.16                   Houston, Texas                    March 1, 2002

         On the dates hereinafter prescribed, for value received, ULTRA
RESOURCES, INC., a Wyoming corporation, (herein called "Borrower"), having an
address at 16801 Greenspoint Park, Suite 370, Houston, Texas 77060, promises to
pay to the order of COMPASS BANK (herein called "Bank"), at its principal
offices at 24 Greenway Plaza, Suite 1401, Houston, Texas 77046, (i) the
principal amount of U.S TWENTY-TWO MILLION, FIVE HUNDRED EIGHTY THOUSAND, SIX
HUNDRED FORTY-FIVE AND 16/100 DOLLARS ($22,580,645.16) or the principal amount
advanced pursuant to the terms of the Credit Agreement (defined herein) as of
the date of maturity hereof, whether by acceleration or otherwise, whichever may
be the lesser, and (ii) interest on the principal balance from time to time
advanced and remaining unpaid from the date of the advance until maturity at a
rate of interest equal to lesser of (a) the "Floating Rate" (as defined and
calculated in the Credit Agreement), or (b) the Maximum Rate (as defined and
calculated in the Credit Agreement). Any increase or decrease in interest rate
resulting from a change in the Maximum Rate shall be effective immediately when
such change becomes effective, without notice to the Borrower, unless Applicable
Law (as defined in the Credit Agreement) requires that such increase or decrease
not be effective until a later time, in which event such increase or decrease
shall be effective at the earliest time permitted under the provisions of such
law.

         Notwithstanding the foregoing, if during any period the Floating Rate
exceeds the Maximum Rate, the rate of interest in effect on this Note shall be
limited to the Maximum Rate during each such period, but at all times thereafter
the rate of interest in effect on this Note shall be the Maximum Rate or, if
there is no Maximum Rate, the Agreed Maximum Rate (as defined below), until the
total amount of interest accrued on this Note equals the total amount of
interest which would have accrued hereon if the Floating Rate had at all times
been in effect.

         This Note is a revolving credit note and it is contemplated that by
reason of prepayments hereon there may be times when no indebtedness is owing
hereunder; but notwithstanding such occurrence, this Note shall remain valid and
in full force and effect as to each principal advance made hereunder subsequent
to each such occurrence. Each principal advance and each payment hereof made
pursuant to this Note shall be reflected by the Bank's records and the aggregate
unpaid amounts reflected by such records shall constitute rebuttably presumptive
evidence of the principal and unpaid, accrued interest remaining outstanding on
this Note.

         "Agreed Maximum Rate" means a per annum rate of seven and three-fourths
percent (7.75%) plus the Floating Rate from time to time in effect, which Agreed
Maximum Rate shall apply only during any period while there is no Maximum Rate
applicable to this Note.

         Other capitalized terms used herein, that are not defined herein, shall
have the meanings prescribed therefor in the Credit Agreement.

         The Borrower and the Bank hereby agree that Chapter 346 of the Texas
Finance Code, shall not apply to this Note or the loan transaction evidenced by,
and referenced in, the Credit

                                                                     MDW
                                                             -------------------
                                                             Borrower's Initials

                                       1

<PAGE>

Agreement (hereinafter defined) in any manner, including without limitation, to
any account or arrangement evidenced or created by, or provided for in, this
Note.

         The principal sum of this Note, after giving credit for unadvanced
principal, if any, remaining at final maturity, shall be due and payable on or
before March 1, 2006; interest to accrue upon the principal sum from time to
time owing and unpaid hereunder shall be due and payable as provided in the
Credit Agreement; provided, however, the final installment of interest hereunder
shall be due and payable not later than the maturity of the principal sum
hereof, howsoever such maturity may be brought about.

         In no event shall the aggregate of the interest on this Note, plus any
other amounts paid in connection with the loan evidenced by this Note which
would under Applicable Law be deemed "interest," ever exceed the maximum amount
of interest which, under Applicable Law, could be lawfully charged on this Note.
The Bank and the Borrower specifically intend and agree to limit contractually
the interest payable on this Note to not more than an amount determined at the
Maximum Rate. Therefore, none of the terms of this Note or any other instruments
pertaining to or securing this Note shall ever be construed to create a contract
to pay interest at a rate in excess of the Maximum Rate, and neither the
Borrower nor any other party liable herefor shall ever be liable for interest in
excess of that determined at the Maximum Rate, and the provisions of this
paragraph shall control over all provisions of this Note or of any other
instruments pertaining to or securing this Note. If any amount of interest taken
or received by the Bank shall be in excess of the maximum amount of interest
which, under Applicable Law, could lawfully have been collected on this Note,
then the excess shall be deemed to have been the result of a mathematical error
by the parties hereto and shall be refunded promptly to the Borrower. All
amounts paid or agreed to be paid in connection with the indebtedness evidenced
by this Note which would under Applicable Law be deemed "interest" shall, to the
extent permitted by Applicable Law, be amortized, prorated, allocated and spread
throughout the full term of this Note.

         This Note is secured by all security agreements, collateral
assignments, mortgages and lien instruments executed by the Borrower (or by any
other party) in favor of Bank One, NA, as Administrative Agent for the Banks,
including those executed simultaneously herewith, those executed heretofore and
those hereafter executed, and including specifically and without limitation the
Security Instruments described and defined in that certain Credit Agreement
dated as of March 22, 2000 by and between Borrower, Ultra Petroleum (USA) Inc.,
and Bank One, Texas, National Association, as amended by that certain First
Amendment to Credit Agreement dated as of July 19, 2001 by and between Borrower
and Bank One, NA, and as mended and restated by that certain First Amended and
Restated Credit Agreement dated March 1, 2002, as amended by the First Amendment
thereto dated November 4, 2002 and the Second Amendment thereto dated May 14,
2003, by and among Borrower, Bank One, NA, as the Administrative Agent, as a
Bank and as LC Issuer, and the several other banks and financial institutions
who are from time to time party thereto as Banks (as may be further amended from
time to time, the "Credit Agreement").

         This Note is the Revolving Note issued pursuant to the Credit
Agreement. Reference is hereby made to the Credit Agreement for a statement of
the rights and obligations of the holder of this Note and the duties and
obligations of the Borrower in relation thereto; but neither this reference to
the Credit Agreement nor any provisions thereof shall affect or impair the
absolute

                                                                     MDW
                                                             -------------------
                                                             Borrower's Initials

                                       2

<PAGE>

and unconditional obligation of the Borrower to pay any outstanding and unpaid
principal of and interest on this Note when due, in accordance with the terms of
the Credit Agreement. Each advance and each payment made pursuant to this Note
shall be reflected by notations made by the Bank on its records and the
aggregate unpaid amounts reflected by the notations on the records of the Bank
shall be deemed rebuttably presumptive evidence of the principal amount owing
under this Note.

         In the event of default in the payment when due of any of the principal
of or any interest on this Note, or in the event of default under the terms of
the Credit Agreement or any of the Security Instruments, or if any event occurs
or condition exists which authorizes the acceleration of the maturity of this
Note under any agreement made by the Borrower, the Bank (or other holder of this
Note) may, at its option, without presentment or demand or any notice to the
Borrower or any other person liable herefor, declare the unpaid principal
balance of and accrued interest on this Note to be immediately due and payable.

         If this Note is collected by suit or through the Probate or Bankruptcy
Court, or any judicial proceeding, or if this Note is not paid at maturity,
however such maturity may be brought about, and is placed in the hands of an
attorney for collection, then the Borrower agrees to pay reasonable and
documented attorneys' fees, not to exceed 10% of the full amount of principal
and interest owing hereon at the time this Note is placed in the hands of an
attorney.

         The Borrower and all sureties, endorsers and guarantors of this Note
waive demand, presentment for payment, notice of nonpayment, protest, notice of
protest, notice of intent to accelerate maturity, notice of acceleration of
maturity, and all other notices, filing of suit and diligence in collecting this
Note or enforcing any of the security herefor, and agree to any substitution,
exchange or release of any such security or the release of any party primarily
or secondarily liable hereon and further agrees that it will not be necessary
for the Bank, in order to enforce payment of this Note by them, to first
institute suit or exhaust its remedies against any Borrower or others liable
herefor, or to enforce its rights against any security herefor, and consent to
any one or more extensions or postponements of time of payment of this Note on
any terms or any other indulgences with respect hereto, without notice thereof
to any of them. The Bank may transfer this Note, and the rights and privileges
of the Bank under this Note shall inure to the benefit of the Bank's
representatives, successors or assigns.

         This Note amends and restates that certain Amended and Restated
Revolving Note dated March 1,2002 in the principal amount of $13,750,000
executed by ULTRA RESOURCES, INC. and payable to the order of Bank One, NA (the
"Prior Note"). All liens and security interests that exist to secure the
indebtedness evidenced by that Prior Note shall continue in force and effect to
secure the indebtedness evidenced by this Note.

                                                                     MDW
                                                             -------------------
                                                             Borrower's Initials

                                       3

<PAGE>

         Executed as of May 14, 2003, but effective as of the date and year
first set forth above.

                                   ULTRA RESOURCES, INC.

Attest:

/s/ Charlotte H. Kauffman          By: /s/ Michael D. Watford
-------------------------              -----------------------------------------
Charlotte H. Kauffman                  Michael D. Watford
Secretary                              President and Chief Executive Officer

                                       4

<PAGE>

                   SECOND AMENDED AND RESTATED REVOLVING NOTE

$35,483,870.97                 Houston, Texas                      March 1, 2002

         On the dates hereinafter prescribed, for value received, ULTRA
RESOURCES, INC., a Wyoming corporation, (herein called "Borrower"), having an
address at 16801 Greenspoint Park, Suite 370, Houston, Texas 77060, promises to
pay to the order of HIBERNIA NATIONAL BANK (herein called "Bank"), at its
principal offices at 313 Carondelet Street, New Orleans, Louisiana 70130, (i)
the principal amount of U.S. THIRTY-FIVE MILLION, FOUR HUNDRED EIGHTY-THREE
THOUSAND, EIGHT HUNDRED SEVENTY AND 97/100 DOLLARS ($35,483,870.97) or the
principal amount advanced pursuant to the terms of the Credit Agreement (defined
herein) as of the date of maturity hereof, whether by acceleration or otherwise,
whichever may be the lesser, and (ii) interest on the principal balance from
time to time advanced and remaining unpaid from the date of the advance until
maturity at a rate of interest equal to lesser of (a) the "Floating Rate" (as
defined and calculated in the Credit Agreement), or (b) the Maximum Rate (as
defined and calculated in the Credit Agreement). Any increase or decrease in
interest rate resulting from a change in the Maximum Rate shall be effective
immediately when such change becomes effective, without notice to the Borrower,
unless Applicable Law (as defined in the Credit Agreement) requires that such
increase or decrease not be effective until a later time, in which event such
increase or decrease shall be effective at the earliest time permitted under the
provisions of such law.

         Notwithstanding the foregoing, if during any period the Floating Rate
exceeds the Maximum Rate, the rate of interest in effect on this Note shall be
limited to the Maximum Rate during each such period, but at all times thereafter
the rate of interest in effect on this Note shall be the Maximum Rate or, if
there is no Maximum Rate, the Agreed Maximum Rate (as defined below), until the
total amount of interest accrued on this Note equals the total amount of
interest which would have accrued hereon if the Floating Rate had at all times
been in effect.

         This Note is a revolving credit note and it is contemplated that by
reason of prepayments hereon there may be times when no indebtedness is owing
hereunder; but notwithstanding such occurrence, this Note shall remain valid and
in full force and effect as to each principal advance made hereunder subsequent
to each such occurrence. Each principal advance and each payment hereof made
pursuant to this Note shall be reflected by the Bank's records and the aggregate
unpaid amounts reflected by such records shall constitute rebuttably presumptive
evidence of the principal and unpaid, accrued interest remaining outstanding on
this Note.

         "Agreed Maximum Rate" means a per annum rate of seven and three-fourths
percent (7.75%) plus the Floating Rate from time to time in effect, which Agreed
Maximum Rate shall apply only during any period while there is no Maximum Rate
applicable to this Note.

         Other capitalized terms used herein, that are not defined herein, shall
have the meanings prescribed therefor in the Credit Agreement.

                                                                     MDW
                                                             -------------------
                                                             Borrower's Initials

<PAGE>

         The Borrower and the Bank hereby agree that Chapter 346 of the Texas
Finance Code, shall not apply to this Note or the loan transaction evidenced by,
and referenced in, the Credit Agreement (hereinafter defined) in any manner,
including without limitation, to any account or arrangement evidenced or created
by, or provided for in, this Note.

         The principal sum of this Note, after giving credit for unadvanced
principal, if any, remaining at final maturity, shall be due and payable on or
before March 1, 2006; interest to accrue upon the principal sum from time to
time owing and unpaid hereunder shall be due and payable as provided in the
Credit Agreement; provided, however, the final installment of interest hereunder
shall be due and payable not later than the maturity of the principal sum
hereof, howsoever such maturity may be brought about.

         In no event shall the aggregate of the interest on this Note, plus any
other amounts paid in connection with the loan evidenced by this Note which
would under Applicable Law be deemed "interest," ever exceed the maximum amount
of interest which, under Applicable Law, could be lawfully charged on this Note.
The Bank and the Borrower specifically intend and agree to limit contractually
the interest payable on this Note to not more than an amount determined at the
Maximum Rate. Therefore, none of the terms of this Note or any other instruments
pertaining to or securing this Note shall ever be construed to create a contract
to pay interest at a rate in excess of the Maximum Rate, and neither the
Borrower nor any other party liable herefor shall ever be liable for interest in
excess of that determined at the Maximum Rate, and the provisions of this
paragraph shall control over all provisions of this Note or of any other
instruments pertaining to or securing this Note. If any amount of interest taken
or received by the Bank shall be in excess of the maximum amount of interest
which, under Applicable Law, could lawfully have been collected on this Note,
then the excess shall be deemed to have been the result of a mathematical error
by the parties hereto and shall be refunded promptly to the Borrower. All
amounts paid or agreed to be paid in connection with the indebtedness evidenced
by this Note which would under Applicable Law be deemed "interest" shall, to the
extent permitted by Applicable Law, be amortized, prorated, allocated and spread
throughout the full term of this Note.

         This Note is secured by all security agreements, collateral
assignments, mortgages and lien instruments executed by the Borrower (or by any
other party) in favor of Bank One, NA, as Administrative Agent for the Banks,
including those executed simultaneously herewith, those executed heretofore and
those hereafter executed, and including specifically and without limitation the
Security Instruments described and defined in that certain Credit Agreement
dated as of March 22, 2000 by and between Borrower, Ultra Petroleum (USA) Inc.,
and Bank One, Texas, National Association, as amended by that certain First
Amendment to Credit Agreement dated as of July 19, 2001 by and between Borrower
and Bank One, NA, and as amended and restated by that certain First Amended and
Restated Credit Agreement dated March 1, 2002, as amended by the First Amendment
thereto dated November 4, 2002 and the Second Amendment thereto dated May 14,
2003, by and among Borrower, Bank One, NA, as the Administrative Agent, as a
Bank and as LC Issuer, and the several other banks and financial institutions
who are from time to time party thereto as Banks (as may be further amended from
time to time, the "Credit Agreement").

                                                                     MDW
                                                             -------------------
                                                             Borrower's Initials

                                       2

<PAGE>

         This Note is the Revolving Note issued pursuant to the Credit
Agreement. Reference is hereby made to the Credit Agreement for a statement of
the rights and obligations of the holder of this Note and the duties and
obligations of the Borrower in relation thereto; but neither this reference to
the Credit Agreement nor any provisions thereof shall affect or impair the
absolute and unconditional obligation of the Borrower to pay any outstanding and
unpaid principal of and interest on this Note when due, in accordance with the
terms of the Credit Agreement. Each advance and each payment made pursuant to
this Note shall be reflected by notations made by the Bank on its records and
the aggregate unpaid amounts reflected by the notations on the records of the
Bank shall be deemed rebuttably presumptive evidence of the principal amount
owing under this Note.

         In the event of default in the payment when due of any of the principal
of or any interest on this Note, or in the event of default under the terms of
the Credit Agreement or any of the Security Instruments, or if any event occurs
or condition exists which authorizes the acceleration of the maturity of this
Note under any agreement made by the Borrower, the Bank (or other holder of this
Note) may, at its option, without presentment or demand or any notice to the
Borrower or any other person liable herefor, declare the unpaid principal
balance of and accrued interest on this Note to be immediately due and payable.

         If this Note is collected by suit or through the Probate or Bankruptcy
Court, or any judicial proceeding, or if this Note is not paid at maturity,
however such maturity may be brought about, and is placed in the hands of an
attorney for collection, then the Borrower agrees to pay reasonable and
documented attorneys' fees, not to exceed 10% of the full amount of principal
and interest owing hereon at the time this Note is placed in the hands of an
attorney.

         The Borrower and all sureties, endorsers and guarantors of this Note
waive demand, presentment for payment, notice of nonpayment, protest, notice of
protest, notice of intent to accelerate maturity, notice of acceleration of
maturity, and all other notices, filing of suit and diligence in collecting this
Note or enforcing any of the security herefor, and agree to any substitution,
exchange or release of any such security or the release of any party primarily
or secondarily liable hereon and further agrees that it will not be necessary
for the Bank, in order to enforce payment of this Note by them, to first
institute suit or exhaust its remedies against any Borrower or others liable
herefor, or to enforce its rights against any security herefor, and consent to
any one or more extensions or postponements of time of payment of this Note on
any terms or any other indulgences with respect hereto, without notice thereof
to any of them. The Bank may transfer this Note, and the rights and privileges
of the Bank under this Note shall inure to the benefit of the Bank's
representatives, successors or assigns.

         This Note amends and restates that certain Amended and Restated
Revolving Note dated March 1, 2002 in the original principal amount of
$21,250,000 executed by ULTRA RESOURCES, INC. and payable to the order of Bank
One, (the "Prior Note"). All liens and security interests that exist to secure
the indebtedness evidenced by that Prior Note shall continue in force and effect
to secure the indebtedness evidenced by this Note.

                                                                     MDW
                                                             -------------------
                                                             Borrower's Initials

                                       3

<PAGE>

         Executed as of May 14, 2003, but effective as of the date and year
first set forth above.

                                       ULTRA RESOURCES, INC.

Attest:

/s/ Charlotte H. Kauffman              By: /s/ Michael D. Watford
-------------------------                  -------------------------------------
Charlotte H. Kauffman                      Michael D. Watford
Secretary                                  President and Chief Executive Officer

                                       4