N-CSR Item 12(b) - Exhibits: Certifications

                           SECTION 906 CERTIFICATION

Pursuant to 18 U.S.C.{section} 1350, the undersigned officers of FEDERATED
MUNICIPAL SECURITIES FUND, INC. (the "Registrant"), hereby certify, to the best
of our knowledge, that the Registrant's Report on Form N-CSR for the period
ended September 30, 2006 (the "Report") fully complies with the requirements of
Section 13(a) or 15(d), as applicable, of the Securities and Exchange Act of
1934 and that the information contained in the Report fairly presents, in all
material respects, the financial condition and results of operations of the
Registrant.


Dated: March 20, 2007

/s/ J. Christopher Donahue
Name: J. Christopher Donahue
Title: President, Principal Executive Officer



Dated: March 20, 2007

/s/ Richard A. Novak
Name: Richard A. Novak
Title: Treasurer, Principal Financial Officer

This certification is being furnished solely pursuant to 18 U.S.C.{section} 1350
and is not being filed as part of the Report or as a separate disclosure
document.