Exhibit 99.1350CERT

         Certification Pursuant to Rule 30a-2(b) under the 1940 Act and
                      Section 906 of the Sarbanes Oxley Act

Pursuant to 18 U.S.C. ss. 1350, the undersigned officer of BlackRock MuniYield
Quality Fund, Inc. (the "Registrant"), hereby certifies, to the best of his
knowledge, that the Registrant's Report on Form N-CSR for the period ended April
30, 2007, (the "Report") fully complies with the requirements of Section 13(a)
of the Securities Exchange Act of 1934, as amended, and that the information
contained in the Report fairly presents, in all material respects, the financial
condition and results of operations of the Registrant.

Date: June 19, 2007


/s/ Robert C. Doll, Jr.
- --------------------------------------
Robert C. Doll, Jr., Chief Executive Officer of
BlackRock MuniYield Quality Fund, Inc.

Pursuant to 18 U.S.C. ss. 1350, the undersigned officer of BlackRock MuniYield
Quality Fund, Inc. (the "Registrant"), hereby certifies, to the best of his
knowledge, that the Registrant's Report on Form N-CSR for the period ended April
30, 2007, (the "Report") fully complies with the requirements of Section 13(a)
of the Securities Exchange Act of 1934, as amended, and that the information
contained in the Report fairly presents, in all material respects, the financial
condition and results of operations of the Registrant.

Date: June 19, 2007


/s/ Donald C. Burke
- --------------------------------------
Donald C. Burke, Chief Financial Officer of
BlackRock MuniYield Quality Fund, Inc.

This certification is being furnished pursuant to Rule 30a-2(b) under the
Investment Company Act of 1940, as amended, and 18 U.S.C. Section 1350 and is
not being filed as part of the Form N-CSR with the Securities and Exchange
Commission