Core Molding (CMT) 10-K 2012 FY Annual report

Exhibit 32(a)

CORE MOLDING TECHNOLOGIES, INC.

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 Core Molding Technologies, Inc. (the “Company”) on Form 10-K for the period ended December 31, 2012 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, Kevin L. Barnett, President, Chief Executive Officer, and Director of the Company, certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 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 results of operations of the Company.

/s/ Kevin L. Barnett

Kevin L. Barnett

President, Chief Executive Officer, and Director

August 12, 2011

March 27, 2013