Report of Independent Registered Public
Accounting Firm

To the Board of Trustees and Shareowners of
Pioneer Mid Cap Value Fund
In planning and performing our audit of the
financial statements of Pioneer Mid Cap Value
Fund  (the Company) as of and for the year
ended October 31, 2012, in accordance with
the standards of the Public Company
Accounting Oversight Board (United States),
we considered the Company'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 Company's internal control
over financial reporting. Accordingly, we
express no such opinion.
The management of the Company 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 Company'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 Company's
internal control over financial reporting and its
operation, including controls over safeguarding
securities, that we consider to be a material
weakness as defined above as of October 31,
2012.
This report is intended solely for the
information and use of management and the
Board of Trustees of Pioneer Mid Cap Value
Fund and the Securities and Exchange
Commission and is not intended to be and
should not be used by anyone other than these
specified parties.



Ernst & Young LLP
Boston, MA

December 26, 2012