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



                            SECTION 906 CERTIFICATION

Pursuant to 18 U.S.C.ss.  1350, the undersigned  officers of Federated Municipal
Securities Income Trust on behalf of Federated California Municipal Income Fund,
Federated Michigan  Intermediate  Municipal Trust,  Federated New York Municipal
Income Fund,  Federated  North Carolina  Municipal  Income Fund,  Federated Ohio
Municipal Income Fund, Federated  Pennsylvania  Municipal Income Fund, Federated
Vermont Municipal Income Fund (the "Registrant"), hereby certify, to the best of
our knowledge,  that the Registrant's  Report on Form N-CSR for the period ended
August 31, 2004 (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:  October 25, 2004

/s/ J. Christopher Donahue

Title: President, Principal Executive Officer



Dated:  October 25, 2004

/s/ Richard J. Thomas

Title: Treasurer, Principal Financial Officer

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