Exhibit (a)(iii) under Form N-1A
                                            Exhibit 3(i) under Item 601/Reg. S-K


                   FEDERATED MUNICIPAL SECURITIES INCOME TRUST

                                Amendment No. 19
                                     to the
                              DECLARATION OF TRUST

                              Dated August 6, 1990


     THIS Declaration of Trust is amended as follows:

A.   Strike the first sentence of Section 5 of Article XII from the  Declaration
     of Trust and substitute in its place the following:

     Section 5. Offices of the Trust, Filing of Copies, Headings,  Counterparts.
     The Trust shall maintain a usual place of business in Massachusetts,  which
     shall be  determined  by the  Trustees,  and shall  continue to maintain an
     office at such address unless  changed by the Trustees to another  location
     in Massachusetts.

     The  undersigned,   President  and  Secretary,   hereby  certify  that  the
above-stated  Amendment is a true and correct  Amendment to the  Declaration  of
Trust,  as adopted by the Board of Trustees at a meeting on the 17th day of May,
2000.

      WITNESS the due execution hereof this 17th day of May, 2000.


/s/ Richard B. Fisher               /s/ John W. McGonigle
------------------------------      ------------------------------
Richard B. Fisher, President        John W. McGonigle, Secretary