T. Rowe Price Mid-Cap Growth Fund (RPMGX) N-CSR Certified annual shareholder report (management investment company)

Item 12(b).
CERTIFICATION UNDER SECTION 906 OF SARBANES-OXLEY ACT OF 2002
Name of Issuer: T. Rowe Price Mid-Cap Growth 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, 2011		/s/ Edward C. Bernard
		Edward C. Bernard
		Principal Executive Officer
Date: February 17, 2011		/s/ Gregory K. Hinkle
		Gregory K. Hinkle
		Principal Financial Officer