WAIVER UNDER CREDIT AGREEMENT

Exhibit 10.32

WAIVER UNDER CREDIT AGREEMENT

among

GASTAR EXPLORATION USA, INC.,

GASTAR EXPLORATION LTD.,

THE LENDERS SIGNATORY HERETO

and

WAYZATA INVESTMENT PARTNERS LLC,

as Administrative Agent

Effective

March 13, 2009

TABLE OF CONTENTS

i

WAIVER UNDER CREDIT AGREEMENT

This WAIVER UNDER CREDIT AGREEMENT (this “ Waiver ”) executed effective as of March 13, 2009 (the “ Effective Date ”) is by and among GASTAR EXPLORATION USA, INC., a Michigan corporation (the “ Borrower ”), GASTAR EXPLORATION LTD., an Alberta, Canada corporation (the “ Parent ”), the lenders party to that certain Credit Agreement dated effective February 16, 2009 by and among the Borrower, the Parent, the lenders party thereto or bound thereby from time to time (the “ Lenders ”), and Wayzata Investment Partners LLC, as administrative agent for the Lenders (in such capacity, the “ Agent ”) (as amended to the Effective Date, the “ Credit Agreement ”).

W I T N E S S E T H :

WHEREAS, the Borrower, the Parent, the Lenders and the Agent are parties to the Credit Agreement; and

WHEREAS, the Borrower and the Parent have requested that the Agent and the Lenders waive any default or right to exercise any remedy as a result of the inability of the Borrower and the Parent to meet the current ratio requirements as required by Section 7.14 of the Credit Agreement;

NOW, THEREFORE, in consideration of the premises and the mutual covenants and agreements contained in the Credit Agreement and herein, the parties hereto agree as follows:

ARTICLE I

DEFINITIONS AND INTERPRETATION

1.1 Terms Defined Above . As used in this Waiver Under Credit Agreement, each of the terms “ Agent ,” “ Borrower ,” “ Credit Agreement ,” “ Effective Date ,” Lenders ,” “ Parent ” and “ Waiver ” shall have the meaning assigned to such term hereinabove.

1.2 Terms Defined in Credit Agreement . Each term defined in the Credit Agreement and used herein without definition shall have the meaning assigned to such term in the Credit Agreement, unless herein expressly provided to the contrary.

1.3 References . References in this Waiver to Exhibit, Article or Section numbers shall be to Exhibits, Articles or Sections of this Waiver, unless expressly stated to the contrary. References in this Waiver to “hereby,” “herein,” “hereinafter,” “hereinabove,” “hereinbelow,” “hereof,” “hereunder” and words of similar import shall be to this Waiver in its entirety and not only to the particular Schedule, Exhibit, Article, or Section in which such reference appears. Specific enumeration herein shall not exclude the general and, in such regard, the terms “includes” and “including” used herein shall mean “includes, without limitation,” or “including, without limitation,” as the case may be, where appropriate. Except as otherwise indicated, references in this Waiver to statutes, sections, or regulations are to be construed as including all statutory or regulatory provisions consolidating, amending, replacing, succeeding, or supplementing the statute, section, or regulation referred to. References in this Waiver to “writing” include printing, typing, lithography, facsimile reproduction, and other means of

reproducing words in a tangible visible form. References in this Waiver to amendments and other contractual instruments shall be deemed to include all exhibits and appendices attached thereto and all subsequent amendments and other modifications to such instruments, but only to the extent such amendments and other modifications are not prohibited by the terms of the Credit Agreement or this Waiver. References in this Waiver to Persons include their respective successors an