Re: Fifth Amendment to Credit Agreement dated as of January 18, 2008 among Approach Resources Inc. ("Borrower"), the Frost National Bank and the institutions named therein ("Lenders") and The Frost National Bank, as Agent ("Agent")

Exhibit 10.1

The Frost National Bank

Gentlemen:

Reference is hereby made to that certain Credit Agreement dated as of January 18, 2008 among Approach Resources Inc., a Delaware corporation (“Borrower”), the Frost National Bank, as Agent (“Agent”), and the Lenders that are signatory parties hereto (the “Lenders”),  as amended by letter amendment dated as of February 19, 2008, letter amendment dated as of May 6, 2008, third amendment dated as of August 26, 2008, fourth amendment dated as of April 8, 2009 and as amended as of the date hereof (as amended, the “Loan Agreement”).  All capitalized terms herein shall have the meanings ascribed to them in the Loan Agreement.

Pursuant to this letter amendment (the “Amendment”), Agent, Lenders and Borrower agree, effective as of the date hereof, to amend the Loan Agreement according to the terms and provisions set forth below.

1.            Amendment to Section 1.   Defined Terms .

Effective as of the date hereof, the definition of “Maturity Date” is deleted in its entirety and the following is substituted therefor:

2.            Extension Fee .  In consideration for Lenders’ agreement to extend the Maturity Date, Borrower shall pay to Agent, for the ratable benefit of Lenders, an extension fee in the amount of $250,000, calculated as 0.25% of the Commitment Amount now in effect.

3.            Ratification by Guarantors .  Each Guarantor hereby ratifies and reaffirms all of its obligations under its Guaranty Agreement (the “Guaranty”) of Borrower's obligations under the Loan Agreement, as amended hereby.  Each Guarantor also hereby agrees that nothing in this Amendment shall adversely affect any right or remedy of Lenders under the Guaranty and that the execution and delivery of this Amendment shall in no way change or modify its obligations as guarantor under the Guaranty.  Although each Guarantor has been informed by Borrower of the matters set forth in this Amendment and such Guarantor has acknowledged and agreed to the same, such Guarantor understands that Agent has no duty to notify such Guarantor or to seek such Guarantor’s acknowledgment or agreement, and nothing contained herein shall create such a duty as to any transaction hereafter.