PostRock Energy (PSTR) 10-K 2011 FY Annual report

Exhibit 32.2

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Annual Report of PostRock Energy Corporation (the “Corporation”) on Form 10-K for the period ended December 31, 2011 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, David J. Klvac, Executive Vice President, Chief Financial Officer and Chief Accounting Officer of the Corporation, certify, pursuant to 18 U.S.C. § 1350, as adopted pursuant to § 906 of the Sarbanes-Oxley Act of 2002, that to the best of my knowledge:

1. The Report fully complies with the requirements of section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

2. The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Corporation.

/s/ DAVID J. KLVAC

David J. Klvac

Executive Vice President, Chief Financial Officer and Chief Accounting Officer

March 8, 2012

The foregoing certification is being furnished solely pursuant to Section 906 of the Act and Rule 13a-14(b) promulgated under the Exchange Act and is not being filed as part of the Report or as a separate disclosure document.