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                                                                   EXHIBIT 10.1

                                 AMENDMENT NO. 1

                                       TO

               OIL & GAS REVOLVING CREDIT AND TERM LOAN AGREEMENT


         THIS AMENDMENT NO.1 (this "Amendment") is entered into as of September
7, 2001, by and among TRANSTEXAS GAS CORPORATION, a Delaware corporation
("Borrower"), the financial institutions set forth on the signature pages hereto
(each a "Lender" and collectively, "Lenders") and GMAC COMMERCIAL CREDIT LLC as
agent for Lenders (in such capacity, "Agent").

                                   BACKGROUND

         Borrower, Agent and Lenders are parties to an Oil & Gas Revolving
Credit and Term Loan Agreement dated as of March 15, 2000 (as amended, restated,
supplemented or otherwise modified from time to time, the "Loan Agreement")
pursuant to which Agent and Lenders provide Borrower with certain financial
accommodations.

         Borrower has requested that Agent and Lenders make certain amendments
to the Loan Agreement, and Agent and Lenders are willing to do so on the terms
and conditions hereafter set forth.

         NOW, THEREFORE, in consideration of any loan or advance or grant of
credit heretofore or hereafter made to or for the account of Borrower by Agent
and Lenders, and for other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the parties hereto hereby agree as
follows:

         1. Definitions. All capitalized terms not otherwise defined herein
shall have the meanings given to them in the Loan Agreement.

         2. Amendment to Loan Agreement. Subject to satisfaction of the
conditions precedent set forth in Section 3 below, the Loan Agreement is hereby
amended as follows:

            (a) Section 7.4 is amended by revising the time periods and
provisions as follows:


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<Table>
<Caption>
                                                             Maximum Amount of Drilling Production
                                   Period                              Payment Liabilities
                  ----------------------------------------- ------------------------------------------
<S>                                                         <C>
                  Closing Date through 10/31/00                            $60,000,000

                  11/1/00 through 1/31/01                                  $57,500,000

                  2/1/01 through 4/30/01                                   $55,000,000

                  5/1/01 through 7/31/01                                   $50,000,000

                  8/1/01 through 8/31/01                                   $45,000,000

                  9/1/01 through 10/31/01                                  $60,000,000

                  11/1/01 through 1/31/02                                  $55,000,000

                  2/1/02 through 4/30/02                                   $45,000,000

                  5/1/02 and thereafter until the end of                   $30,000,000
                  the Term

</Table>

            (b)      Section 9.3 is amended by adding a new second sentence as
follows:

                     "Notwithstanding the foregoing, Borrower may deliver to
            Agent the Proved Reserves Report prepared as of a recent date (but
            no earlier than August 1, 2001) on or before November 1, 2001."

         3. Conditions of Effectiveness. This Amendment shall become effective
upon satisfaction of the following condition precedent: Agent shall have
received six (6) copies of this Amendment executed by Borrower and Required
Lenders and consented and agreed to by Guarantors.

         4. Representations and Warranties. Borrower hereby represents and
warrants as follows:

            (a) This Amendment and the Loan Agreement, as amended hereby,
constitute legal, valid and binding obligations of Borrower and are enforceable
against Borrower in accordance with their respective terms.

            (b) Upon the effectiveness of this Amendment, Borrower hereby
reaffirms all covenants, representations and warranties made in the Loan
Agreement to the extent the same are not amended hereby and agree that all such
covenants, representations and warranties shall be deemed to have been remade as
of the effective date of this Amendment.

            (c) No Event of Default or Default has occurred and is continuing or
would exist after giving effect to this Amendment.

            (d) Borrower has no defense, counterclaim or offset with respect to
the Loan Agreement.

         5. Effect on the Loan Agreement.

            (a) Upon the effectiveness of Section 2 hereof, each reference in
the Loan Agreement to "this Agreement," "hereunder," "hereof," "herein" or words
of like import shall mean and be a reference to the Loan Agreement as amended
hereby.

            (b) Except as specifically amended herein, the Loan Agreement, and
all other documents, instruments and agreements executed and/or delivered in
connection therewith, shall remain in full force and effect, and are hereby
ratified and confirmed.


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            (c) The execution, delivery and effectiveness of this Amendment
shall not operate as a waiver of any right, power or remedy of Agent or Lenders,
nor constitute a waiver of any provision of the Loan Agreement, or any other
documents, instruments or agreements executed and/or delivered under or in
connection therewith.

         6. Governing Law. This Amendment shall be binding upon and inure to the
benefit of the parties hereto and their respective successors and assigns and
shall be governed by and construed in accordance with the laws of the State of
New York.

         7. Headings. Section headings in this Amendment are included herein for
convenience of reference only and shall not constitute a part of this Amendment
for any other purpose.

         8. Counterparts; Facsimile. This Amendment may be executed by the
parties hereto in one or more counterparts, each of which shall be deemed an
original and all of which when taken together shall constitute one and the same
agreement. Any signature delivered by a party by facsimile transmission shall be
deemed to be an original signature hereto.

         IN WITNESS WHEREOF, this Amendment has been duly executed as of the day
and year first written above.

                               TRANSTEXAS GAS CORPORATION

                               By:
                                   ---------------------------------------------
                                   Name:
                                   Title:


                               GMAC COMMERCIAL CREDIT LLC, as Agent and Lender

                               By:
                                   ---------------------------------------------
                                   Name:
                                   Title:

                               Commitment Percentage:     61.90477%


                               CREDIT SUISSE FIRST BOSTON
                               MANAGEMENT, as a Lender

                               By:
                                   ---------------------------------------------
                                   Name:
                                   Title:

                               Commitment Percentage:     12.69841%


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                               ANGELO GORDON & CO. L.P.

                               By:
                                   ---------------------------------------------
                                   Name:
                                   Title:

                               Commitment Percentage:     12.69841%


                               OAKTREE CAPITAL MANAGEMENT, as a
                               general partner and investment manager of
                               certain funds and accounts it manages, as Lender

                               By:
                                   ---------------------------------------------
                                   Name:
                                   Title:

                               Commitment Percentage:     12.698411%


  CONSENTED AND AGREED TO:

  GALVESTON BAY PROCESSING CORPORATION,
   as Guarantor

By:
    ----------------------------------
       Name:
       Title:


GALVESTON BAY PIPELINE COMPANY,
 as Guarantor

By:
    ----------------------------------
       Name:
       Title:



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