Exhibit 32.1

CERTIFICATION OF CHIEF EXECUTIVE OFFICER

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 on Form 10-Q of The Dun & Bradstreet Corporation (the “Company”) for the period ending June 30, 2005 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, Steven W. Alesio, Chief Executive Officer 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), as applicable, 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.

By:  /s/ Steven W. Alesio

Steven W. Alesio

Chairman, Chief Executive Officer & President

August 4, 2005

A signed original of this written statement required by Section 906, or other document authenticating, acknowledging, or otherwise adopting the signature that appears in typed form within the electronic version of this written statement required by Section 906, has been provided to The Dun & Bradstreet Corporation and will be retained by The Dun & Bradstreet Corporation and furnished to the Securities and Exchange Commission or its staff upon request. The foregoing certification is being furnished solely pursuant to 18 U.S.C. Section 1350 and is not being filed as part of the Report or as a separate disclosure document.

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