Exhibit 32.1

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 Cass Information Systems, Inc. (“the Company”) on Form 10-K for the period ended December 31, 2017, as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, Eric H. Brunngraber, Chairman, President and Chief Executive Officer of the Company, certify, pursuant to 18 U.S.C. § 1350, as adopted pursuant to § 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/ Eric H. Brunngraber

Eric H. Brunngraber

Chairman, President and Chief Executive Officer

(Principal Executive Officer)

February 28, 2018

A signed original of this written statement required by Section 906 has been provided to Cass Information Systems, Inc. and will be retained by Cass Information Systems, Inc. and furnished to the Securities and Exchange Commission or its staff upon request.