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                                                                  Exhibit 10.15


                                 AMENDMENT THREE
                  TO SECOND AMENDED AND RESTATED LOAN AGREEMENT


      WHEREAS, that certain Second Amended and Restated Loan Agreement (the
"LOAN AGREEMENT") dated as of June 5, 1998 was executed by Matador E&P
Company, a Texas corporation (hereinafter referred to as "BORROWER"), Matador
Petroleum Corporation, a Texas corporation (hereinafter referred to as
"PARENT"), the lenders named therein, Comerica Bank-Texas, as Agent (in such
capacity, together with its successors in such capacity, "AGENT") and
Comerica Bank-Texas, as Issuing Lender (in such capacity, together with its
successors in such capacity, "ISSUING LENDER"); and

      WHEREAS, the parties desire to increase the Borrowing Base and to
modify the Revolving Credit Commitments of the Lenders;

      NOW THEREFORE, in consideration of the premises and other value, the
receipt and sufficiency of which are hereby acknowledged, Borrower, Parent,
Lenders, Issuing Lender and Agent hereby agree as follows:

      1.    SECTION 5(a) of the Loan Agreement is hereby amended in its
entirety to read as follows:

            "(a)  INITIAL BORROWING BASE.  During the period from August 18,
      2000 to the  date a new Borrowing Base is made effective, the Borrowing
      Base shall be $60,000,000."

      2. SCHEDULE 1.2 of the Loan Agreement is amended in its entirety by
substituting therefor the SCHEDULE 1.2 attached to this Amendment.

      3. The effectiveness of this Amendment is subject to the condition
precedent that the Lenders shall have received (or waived receipt of) the
following, each duly executed and delivered and in form and substance and dated
as of a date satisfactory to the Lenders and their legal counsel, or that the
following shall be fulfilled, as the case may be:

            (a)    This Amendment executed by Borrower, Parent and, where
      appropriate, by NZX Corporation and Matador Operating Company;

            (b)    Renewal Notes payable to the order of Union Bank, to the
      order of Bank of Texas, N.A. and to the order of Comerica in the
      principal amounts of $33,333,000 $16,667,000.00 and $50,000,000.00,
      respectively;

            (c) Legal opinion of counsel to Borrower addressing the due
      organization and good standing of Borrower and Parent, the due
      authorization and execution of this

                                     -1-


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      Amendment by Borrower and Parent, and the enforceability of this Amendment
      and the renewal notes;

            (d) Such deeds of trust, mortgages and modifications and
      extensions of existing deeds of trust and mortgages as Lenders shall
      require;

            (e) Evidence of payment of all reasonable fees and expenses of or
      incurred by the Agent and its legal counsel in connection with this
      Amendment and payment of a borrowing base increase fee of $3,700 to Union
      Bank, $5,000 to Bank of Texas, N.A. and $1,300 to Comerica;

            (f) The representations and warranties contained in the Loan
      Agreement, as amended hereby, shall be true and correct in all material
      respects as of the date hereof, with the same force and effect as though
      made on and as of this date;

            (g) No material adverse change shall have occurred in the business,
      operations, financial condition or prospects of Borrower or Parent, and no
      material adverse litigation shall be pending or, to the knowledge of
      Borrower or Parent, threatened against Borrower or Parent; and

            (h) All corporate proceedings and all documents required to be
      completed and executed by the provisions of this Amendment shall be
      satisfactory in form and substance to Lenders.

All amendments of the Loan Agreement contained herein are, subject to the
satisfaction of the above listed conditions precedent, effective as of August
18, 2000.

      4. Each of Parent, Matador Operating Company and NZX Corporation (each a
"GUARANTOR", and collectively, "GUARANTORS") (i) consents, acknowledges, and
agrees to the execution, delivery, and performance of this Amendment, (ii)
acknowledges and agrees that this Amendment does not diminish, waive, or release
such Guarantor's obligations under its Unconditional Guaranty dated as of June
5, 1998, in the case of Parent and Matador Operating Company, and as of January
18, 1999, in the case of NZX Corporation, (iii) ratifies and confirms such
Guarantor's obligations pursuant to its Unconditional Guaranty.

      5. Borrower shall pay all reasonable out-of-pocket expenses arising in
connection with the preparation, execution, delivery and administration of this
Amendment, including but not limited to, all reasonable legal fees and expenses
incurred by Agent.

      6. Except to the extent amended hereby, all terms, provisions and
conditions of the Loan Agreement shall continue in full force and effect and
shall remain enforceable and binding.

                                     -2-


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      7. This Amendment may be executed in any number of counterparts, each of
which shall for all purposes be deemed an original and all of which are
identical. All parties need not execute the same counterpart.

      8. Borrower and Parent represent and warrant that all the representations
and warranties contained in the Loan Agreement, as amended hereby, are true and
correct in all material respects as of the date hereof, with the same force and
effect as though made on and as of this date.

      9. This Amendment shall be construed in accordance with and governed by
the laws of the State of Texas, without regard to its conflict of law
principles, and shall be binding upon and inure to the benefit of the parties
hereto and their respective successors and assigns.

      10. THIS AMENDMENT AND THE OTHER LOAN DOCUMENTS 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
UNWRITTEN ORAL AGREEMENTS BETWEEN THE PARTIES.

      In consideration of the foregoing, this Amendment Three is executed as of
August 18, 2000.

                                    BORROWER:

                                    MATADOR E&P COMPANY

                                    By: /s/ Roger S. Manny
                                        ----------------------------
                                    Its: Vice President
                                         ----------------------------

                                    PARENT:

                                    MATADOR PETROLEUM CORPORATION


                                    By: /s/ Roger S. Manny
                                        ----------------------------
                                    Its: Vice President
                                         ----------------------------

                                     -3-


<PAGE>


                                    AGENT:

                                    COMERICA BANK-TEXAS

                                    By: /s/ David Montgomery
                                       ---------------------------------
                                    Its: Vice President
                                        ---------------------------------

                                    ISSUING LENDER:

                                    COMERICA BANK-TEXAS

                                    By: /s/ David Montgomery
                                       ---------------------------------
                                    Its: Vice President
                                        ---------------------------------


                                    LENDERS:

                                    COMERICA BANK-TEXAS

                                    By: /s/ David Montgomery
                                       ---------------------------------
                                    Its: Vice President
                                        ---------------------------------



                                    UNION BANK OF CALIFORNIA, N.A.

                                    By: /s/ Dustin Gaspari
                                       ---------------------------------
                                    Its: Vice President
                                        ---------------------------------

                                    BANK OF TEXAS, N.A.

                                    By: /s/ Frank T. Smith, Jr.
                                       ---------------------------------
                                    Its: Executive Vice President
                                        ---------------------------------

                                     -4-


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CONSENTING GUARANTORS:

MATADOR OPERATING COMPANY

By: /s/ Roger S. Manny
    ----------------------------
Its: Vice President
     ----------------------------

NZX CORPORATION

By: /s/ Roger S. Manny
    ----------------------------
Its: Vice President
     ----------------------------

                                     -5-


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                                  SCHEDULE 1.2

                           REVOLVING CREDIT COMMITMENT


Comerica Bank-Texas                 $30,000,000       50%

Union Bank of California, N.A.      $20,000,000       33.333%

Bank of Texas, N.A.                 $10,000,000       16.667%

                                     -6-