Duff & Phelps (DUF) 10-Q 2011 Q2 Quarterly report

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 Quarterly Report of Duff & Phelps Corporation, (the “Company”) on Form 10-Q for the quarter ended June 30, 2011 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, Noah Gottdiener, Chairman and Chief Executive Officer of the Company, hereby certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that to the best of my knowledge:

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 for the periods presented therein.

Date: July 27, 2011

/s/ Noah Gottdiener

__________________________________

NOAH GOTTDIENER

Chairman of the Board and

Chief Executive Officer