<DOCUMENT>
<TYPE>EX-99
<SEQUENCE>2
<FILENAME>poalasman.txt
<DESCRIPTION>POWER OF ATTORNEY
<TEXT>
                                POWER OF ATTORNEY



The  undersigned  on his or her own behalf  and on behalf of his or her  estate,
heirs and assigns hereby  constitutes and appoints Susan S. Newton,  Christopher
R. Bohane,  Timothy M. Fagan,  Susan A. Pereira and Brian E. Langenfeld and each
of them singly as true and lawful  attorneys with full power to them and each of
them, to execute,  on behalf of the  undersigned,  in the capacity listed below,
any and all  statements or reports under Section 16 of the  Securities  Exchange
Act of 1934, as amended,  with respect to the beneficial ownership of reportable
securities  issued  by MFS  High  Income  Municipal  Trust  and MFS  High  Yield
Municipal  Trust  including,  without  limitation,  all  initial  statements  of
beneficial  ownership  on  Form 3,  all  statements  of  changes  of  beneficial
ownership on Form 4 and all annual statements of beneficial ownership on Form 5,
and any and all other  documents that may be required,  from time to time, to be
filed with the  Securities  and  Exchange  Commission,  to  execute  any and all
amendments or supplements to any such statements or forms, and to file the same,
with all exhibits thereto, and other documents in connection therewith, with the
Securities and Exchange  Commission,  granting to said attorney,  full power and
authority  to do so and  perform  each and  every act and  thing  requisite  and
necessary  to be done in and about the  premises,  as fully to all  intents  and
purposes as the undersigned  (or his or her estate,  heirs and assigns) might or
could do in person,  hereby  ratifying and confirming all that said attorneys or
any of them may lawfully do or cause to be done by virtue hereof.

IN WITNESS WHEREOF,  the undersigned has set his or her hand on this 20th day of
June, 2007.



GARY A. LASMAN
Gary A. Lasman
</TEXT>
</DOCUMENT>
