Report of Independent Registered Public Accounting
Firm

To the Shareholders and
Board of Directors of Pioneer Trust Series IV:
In planning and performing our audit of the financial
statements of Pioneer Trust Series IV (comprised of
Pioneer Classic Balanced Fund, Pioneer Government
Income Fund, Pioneer Institutional Money Market
Fund, and Pioneer Treasury Reserves Fund) as of and
for the year ended July 31, 2008, 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 Pioneer Trust Series IV 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 Pioneer Trust Series IV'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 July 31, 2008.
This report is intended solely for the information and
use of management and the Board of Directors of
Pioneer Series Trust IV and the Securities and
Exchange Commission and is not intended to be and
should not be used by anyone other than these
specified parties.



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Boston, Massachusetts
September 19, 2008