EXHIBIT 32.1

CERTIFICATIONS PURSUANT TO

18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

Certification of Principal Executive Officer

In connection with the Quarterly Report of UnitedHealth Group Incorporated (the “Company”) on Form 10-Q for the period ended March 31, 2012 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, Stephen J. Hemsley, certify, pursuant to 18 U.S.C. § 1350, as adopted pursuant to § 906 of the Sarbanes-Oxley Act of 2002, that to 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.

May 3, 2012	/s/    STEPHEN J. HEMSLEY
	Stephen J. Hemsley President and Chief Executive Officer

Certification of Principal Financial Officer

In connection with the Quarterly Report of UnitedHealth Group Incorporated (the “Company”) on Form 10-Q for the period ended March 31, 2012 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, David S. Wichmann, certify pursuant to 18 U.S.C. § 1350, as adopted pursuant to § 906 of the Sarbanes-Oxley Act of 2002, that to 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.

May 3, 2012	/s/    DAVID S. WICHMANN
	David S. Wichmann Executive Vice President and Chief Financial Officer of UnitedHealth Group and President of UnitedHealth Group Operations