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 on Form 10-K of Century Bancorp, Inc. (the “Company”) for the year ended December 31, 2005, as filed with the Securities and Exchange Commission on March 14, 2006, each of the undersigned, certifies, to the best knowledge and belief of the signatory, 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/ Marshall M. Sloane Marshall M. Sloane

Chairman and CEO

Date: March 14, 2006