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                                                                     EXHIBIT 4.1




                          TRANSTEXAS GAS CORPORATION,
                                     Issuer

                                      and

                      TRANSTEXAS TRANSMISSION CORPORATION,
                                   Guarantor


                                      and


                FIRSTAR BANK OF MINNESOTA, NATIONAL ASSOCIATION,
                             successor by merger to
                      AMERICAN BANK NATIONAL ASSOCIATION,
                                    Trustee




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                          FIRST SUPPLEMENTAL INDENTURE

                            Dated as of May 29, 1997

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                                  $800,000,000
                     11 1/2% Senior Secured Notes due 2002



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         THIS FIRST SUPPLEMENTAL INDENTURE, dated as of May 29, 1997 (the
"First Supplemental Indenture"), is made and entered into by and among
TRANSTEXAS GAS CORPORATION, a Delaware corporation (the "Company"), and
TRANSTEXAS TRANSMISSION CORPORATION, a Delaware corporation ("TTC"), and
FIRSTAR BANK OF MINNESOTA, NATIONAL ASSOCIATION, successor by merger to
AMERICAN BANK NATIONAL ASSOCIATION (the "Trustee"), under an Indenture dated as
of June 15, 1995, 1993, by and among the Company, TTC and the Trustee (the
"Original Indenture").  All capitalized terms used in this First Supplemental
Indenture that are defined in the Original Indenture, either directly or by
reference therein, have the meanings assigned to them therein, except to the
extent such terms are defined in this First Supplemental Indenture or the
context clearly requires otherwise.

         WHEREAS, Section 9.02 of the Original Indenture provides, among other
things, that, subject to Section 6.8 of the Original Indenture, the Obligors,
when authorized by Board Resolutions, and the Trustee may, with the written
consent of the Holders of requisite percentage in aggregate principal amount of
the outstanding securities first having been obtained and delivered to the
Company and the Trustee, may amend or supplement the Original Indenture or the
Securities or enter into an indenture or indentures supplemental to the
Original Indenture for the purpose of adding any provisions to or changing in
any manner or eliminating any of the provisions of the Original Indenture or
the Securities or of modifying in any manner the rights of the Holders under
Original Indenture or the Securities; and

         WHEREAS, in response to the Company's Consent Solicitation Statement
dated May 14, 1997 (the "Solicitation"), Holders of at least 66-2/3% of the
aggregate principal amount of the outstanding Notes consented in writing to the
adoption of the amendments to the Original Indenture that are set forth in
Article I of this First Supplemental Indenture (the "Proposed Amendments")
without, as of May 28, 1997, the date on which the Company certified the
receipt of such written consents to the Trustee, subsequent revocation; and

         WHEREAS, the Boards of Directors of the Obligors have adopted
resolutions authorizing and approving the Proposed Amendments, and such
resolutions are in full force and effect on the date hereof; and

         WHEREAS, the Company, TTC and the Trustee are executing and delivering
this First Supplemental Indenture in order to effect and evidence the adoption
of the Proposed Amendments;

         NOW, THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the parties to this First
Supplemental Indenture hereby agree as follows:

                                   ARTICLE I

                        AMENDMENTS TO ORIGINAL INDENTURE

         Section 1.01. Amendment to Section 4.14.  The first sentence of
Section 4.14 of the Original Indenture is hereby amended and restated in its
entirety to read as follows:

                       (a)    The Company shall not, and shall not permit any
                 of its Subsidiaries to, consummate an Asset Sale, unless (A)
                 an amount equal to the Net Cash Proceeds therefrom is (i)
                 applied to the repurchase of Notes pursuant to an Offer to
                 Purchase and/or pursuant to a tender offer as described in
                 clause (y) of the fifth sentence of Section 12.15(a), (ii)
                 used to make cash payments in the ordinary course of business
                 and consistent with past practices that are not otherwise
                 prohibited by this Indenture, provided that the aggregate
                 amount so used pursuant to this clause (ii) from and after the
                 Issue Date does not exceed $50,000,000 (excluding amounts used
                 to acquire any Capital Assets in accordance with clause (iii)
                 below) or (iii) used to acquire Capital Assets for use in a
                 Related Business within 180 days after the date of such Asset
                 Sale, provided that the Company's most recent Reserve Report
                 indicates that
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                 the Company, after giving effect to the Asset Sale and to the
                 addition of proved reserves associated with any Exchange
                 Assets acquired in connection with such Asset Sale, has proved
                 reserves at least equal to 1 Tcfe of natural gas or with an
                 SEC PV10 of at least $900,000,000; and (B) in the case of any
                 Asset Sale or series of related Asset Sales for total proceeds
                 in excess of $5,000,000, at least 85% of the value of the
                 consideration for such Asset Sale consists of cash, Exchange
                 Assets or Permitted Capital Stock or any combination thereof.

         Section 1.02. Amendment to Section 4.16.  The second sentence of
Section 4.16 of the Original Indenture is hereby amended and restated in its
entirety to read as follows:

                 If the Company shall subsequently sell or otherwise transfer
                 all of the Capital Stock of any Guarantor (including but not
                 limited to TTC) held by the Company or shall subsequently sell
                 or transfer or cause to be sold or transferred all or
                 substantially all of the assets of such Guarantor (including
                 but not limited to TTC), the Guarantee required hereby shall
                 be discharged and terminated, and any such Guarantor
                 (including but not limited to TTC) shall be released from any
                 Security Documents to which it is a party, provided that the
                 capital stock or assets, as the case may be, of such Guarantor
                 sold or transferred are released from the Liens of the
                 Security Documents.

         Section 1.03. Amendment to Section 4.17.  Section 4.17 of the Original
Indenture is hereby amended and restated in its entirety to read as follows:

                       Section 4.17   Restriction on Sale and Issuance of
                 Subsidiary Stock.  The Company shall not sell, and shall not
                 permit any of its Subsidiaries to, issue or sell, any shares
                 of Capital Stock of any Subsidiary of the Company to any
                 Person other than the Company or a Wholly Owned Subsidiary of
                 the Company, except that either the Company or TTC may sell
                 Qualified Capital Stock of TTC, provided (i) TTC is not
                 engaged in any business or activity other than that of TTC as
                 of the date hereof, (ii) the Company continues to own Capital
                 Stock of TTC representing (x) at least a majority of the
                 equity interest in TTC and (y) the voting power, under
                 ordinary circumstances, to elect the directors of TTC, and
                 (iii) the Company uses the net proceeds of such sale for one
                 of the purposes specified in the first sentence of Section
                 4.14, and (B) the Company may sell Qualified Capital Stock of
                 TTC, provided the Company shall be required to comply with the
                 requirements of Section 4.14 in connection with such sale and
                 provided further that the Company concurrently with such sale
                 deposits in the Collateral Account an amount equal to the
                 greater of (x) $846,000,000 and (y) the Release Amount
                 therefor.

         Section 1.04. Amendment to Section 12.15.  The first paragraph of
Section 12.15(a) of the Original Indenture is hereby amended by adding a new
sentence immediately following the fourth sentence of such first paragraph, to
read as follows:

                 Notwithstanding anything herein to the contrary, if any funds
                 are deposited into the Collateral Account pursuant to Section
                 4.17 (a "Section 4.17 Deposit"), the amount so deposited shall
                 be retained in the Collateral Account until the earlier of (x)
                 consummation of an Offer to Purchase made in accordance with
                 the terms of Section 4.14 following such Section 4.17 Deposit
                 or (y) consummation of a tender offer made by the Company
                 following such Section 4.17 Deposit to purchase all of the
                 outstanding Securities at a price at least equal to the
                 Purchase Price that would be payable therefor if such
                 Securities were then being purchased





                                      
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                 pursuant to an Offer to Purchase made in accordance with the
                 terms of Section 4.14.  Concurrently with the consummation of
                 such Offer to Purchase or such tender offer, as the case may
                 be, the Company may withdraw such amount of the Section 4.17
                 Deposit, up to the full amount thereof, and utilize the amount
                 so withdrawn for the purpose of paying the Offer Price related
                 to such Offer to Purchase, or the purchase price related to
                 such tender offer, as the case may be, and any amount not used
                 to consummate such Offer to Purchase or such tender offer, as
                 the case may be, may be withdrawn by the Company and used for
                 general corporate purposes without restriction.

         Section 1.05. Amendment to Section Article XIV.  Article XIV of the
Original Indenture is hereby amended by adding a new Section immediately
following Section 14.14 of the Original Indenture, to read as follows:

                       Section 14.15  TTC No Longer Party Upon Certain
                 Events.  Notwithstanding anything herein to the contrary, from
                 and after any sale or transfer of all of the Capital Stock of
                 TTC held by the Company or any sale or transfer of all or
                 substantially all of the assets of TTC, as permitted herein,
                 TTC shall cease to be a party hereto, and no obligations or
                 liabilities shall accrue to TTC hereunder or under any of the
                 Security Documents after TTC so ceases to be a party hereto;
                 provided that the capital stock or assets, as the case may be,
                 of TTC sold or transferred are released from the Liens of the
                 Security Documents.

                                   ARTICLE II

                               GENERAL PROVISIONS

         Section 2.01. Ratification of Indenture.  The Original Indenture is in
all respects acknowledged, ratified and confirmed, and shall continue in full
force and effect in accordance with the terms thereof and as supplemented by
this First Supplemental Indenture.  The Original Indenture and this First
Supplemental Indenture shall be read, taken and construed as one and the same
instrument.

         Section 2.02. Effect of Headings.  The Article and Section headings in
this First Supplemental Indenture are for convenience only and shall not affect
the construction of this First Supplemental Indenture.

         Section 2.03. Severability.  In case any one or more of the provisions
in this First Supplemental Indenture shall be held invalid, illegal or
unenforceable, in any respect for any reason, the validity, legality and
enforceability of any such provision in every other respect and of the
remaining provisions shall not in any way be affected or impaired thereby, it
being intended that all of the provisions hereof shall be enforceable to the
full extent permitted by law.

         Section 2.04. Governing Law.  THIS FIRST SUPPLEMENTAL INDENTURE SHALL
BE CONSTRUED IN ACCORDANCE WITH AND GOVERNED BY THE LAWS OF THE STATE OF NEW
YORK.

         Section 2.05. Counterparts.  This First Supplemental Indenture may be
executed in any number of counterparts, each of which so executed shall be
deemed to be an original, but all such counterparts shall together constitute
the same instrument.

                [THE NEXT-FOLLOWING PAGE IS THE SIGNATURE PAGE]





                                      
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         IN WITNESS WHEREOF, the parties have caused this First Supplemental
Indenture to be duly executed as of day and year first above written.

                                            TRANSTEXAS GAS CORPORATION
                                            
                                            
                                            
Attest: /s/ TIM MOORE                       By: /s/ ARNOLD H. BRACKENRIDGE
       --------------------------------        ----------------------------
         Tim Moore, Assistant Secretary     Name:   Arnold H. Brackenridge
                                            Title:  President
                                            
                                            
                                            TRANSTEXAS TRANSMISSION
                                            CORPORATION
                                            
                                            
Attest: /s/ TIM MOORE                       By: /s/ ARNOLD H. BRACKENRIDGE
       --------------------------------        ----------------------------
         Tim Moore, Assistant Secretary     Name:   Arnold H. Brackenridge
                                            Title:  President
                                            
                                            FIRSTAR BANK OF MINNESOTA,
                                            NATIONAL ASSOCIATION, Trustee
                                            
                                            
                                            
                                            By: /s/ FRANK P. LESLIE, III
                                               ----------------------------
                                            Name:   Frank P. Leslie, III
                                            Title:   Vice President