Report of Independent Registered Public Accounting Firm


To the Shareholders and Board of Trustees of
MFS High Yield Municipal Trust

In  planning  and  performing  our audit of the financial statements of MFS High
Yield Municipal Trust (the Fund) as of and for the year ended November 30, 2013,
in accordance with the standards  of  the  Public  Company  Accounting Oversight
Board (United States), we considered the Fund's internal control  over financial
reporting,  including  controls  over  safeguarding  securities, as a basis  for
designing our auditing procedures for the purpose of expressing  our  opinion on
the financial statements and to comply with the requirements of Form N-SAR,  but
not  for the purpose of expressing an opinion on the effectiveness of the Fund's
internal  control  over  financial  reporting.  Accordingly,  we express no such
opinion.

The  management  of  the  Fund  is responsible for establishing and  maintaining
effective  internal  control  over  financial   reporting.  In  fulfilling  this
responsibility, estimates and judgments by management are required to assess the
expected benefits and related costs of controls.  A  company's  internal control
over  financial reporting is a process designed to provide reasonable  assurance
regarding  the  reliability  of  financial  reporting  and  the  preparation  of
financial statements for external purposes in accordance with generally accepted
accounting  principles.  A  company's  internal control over financial reporting
includes those policies and procedures that  (1)  pertain  to the maintenance of
records   that,  in  reasonable  detail,  accurately  and  fairly  reflect   the
transactions  and  dispositions  of  the  assets  of  the  company;  (2) provide
reasonable  assurance  that  transactions  are  recorded  as necessary to permit
preparation  of  financial  statements  in  accordance  with generally  accepted
accounting principles, and that receipts and expenditures  of  the  company  are
being made only in accordance with authorizations of management and directors of
the company; and (3) provide reasonable assurance regarding prevention or timely
detection  of unauthorized acquisition, use or disposition of a company's assets
that could have a material effect on the financial statements.

Because of its  inherent  limitations, internal control over financial reporting
may not prevent or detect misstatements.  Also, projections of any evaluation of
effectiveness to future periods are subject to the risk that controls may become
inadequate because of changes in conditions,  or  that  the degree of compliance
with the policies or procedures may deteriorate.

A deficiency in internal control over financial reporting exists when the design
or operation of a control does not allow management or employees,  in the normal
course   of   performing   their   assigned  functions,  to  prevent  or  detect
misstatements on a timely basis. A material  weakness  is  a  deficiency,  or  a
combination  of deficiencies, in internal control over financial reporting, such
that there is  a  reasonable  possibility  that  a  material misstatement of the
company's  annual  or  interim financial statements will  not  be  prevented  or
detected on a timely basis.














Our consideration of the  Fund's  internal  control over financial reporting was
for  the  limited  purpose  described  in  the first  paragraph  and  would  not
necessarily disclose all deficiencies in internal control that might be material
weaknesses  under  standards  established  by  the   Public  Company  Accounting
Oversight Board (United States). However, we noted no deficiencies in the Fund's
internal control over financial reporting and its operation,  including controls
over  safeguarding  securities, which we consider to be a material  weakness  as
defined above as of November 30, 2013.

This report is intended solely for the information and use of management and the
Board of Trustees of  MFS  High  Yield  Municipal  Trust  and the Securities and
Exchange Commission and is not intended to be and should not  be  used by anyone
other than these specified parties.


                                                 /s/ ERNST & YOUNG, LLP
Boston, Massachusetts
January 15, 2014