Item 12(b).

CERTIFICATION UNDER SECTION 906 OF SARBANES-OXLEY ACT OF 2002
Name of Issuer: T. Rowe Price Equity Index 500 Fund
In connection with the Report on Form N-CSR for the above named Issuer, the undersigned hereby
certifies, to the best of his knowledge, that:
1.	The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities
	Exchange Act of 1934;
2.	The information contained in the Report fairly presents, in all material respects, the financial
	condition and results of operations of the Issuer.

 

Date: February 17, 2012	/s/ Edward C. Bernard
	Edward C. Bernard
	Principal Executive Officer
Date: February 17, 2012	/s/ Gregory K. Hinkle
	Gregory K. Hinkle
	Principal Financial Officer