Carbon Energy (CRBO) 10-Q 2011 Q3 Quarterly report

Exhibit 32.1

Certification of CEO 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 Quarterly Report of Carbon Natural Gas Company (the “Company”) on Form 10-Q for the period ended September 30, 2011 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), Patrick R. McDonald, President and Chief Executive Officer of the Company, hereby certifies, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, to the best of his knowledge, that:

(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 result of operations of the Company.

/s/ Patrick R. McDonald

Patrick R. McDonald,

Chief Executive Officer

November 14, 2011

This certification accompanies this Report pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 and shall not be deemed filed by the Company for purposes of Section 18 of the Securities Exchange Act of 1934, as amended.

A signed original of this written statement required by Section 906 has been provided to Carbon Natural Gas Company and will be retained by Carbon Natural Gas Company and furnished to the Securities and Exchange Commission or its staff upon request.