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<PAGE> PAGE 2
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<PAGE> PAGE 3
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<PAGE> PAGE 4
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<PAGE> PAGE 5
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<PAGE> PAGE 7
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<PAGE> PAGE 8
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SIGNATURE STEPHANIE D. PIERCE
TITLE ASSISTANT TRESURER
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</TABLE>
Report of Independent Auditors
To the Shareholders and Board of Trustees of
Dreyfus Institutional Money Market Fund, Inc.
In planning and performing our audit of the financial statements of Dreyfus
Institutional Money Market Fund (comprising the Money Market Series and the
Government Securities Series) for the year ended December 31, 1999, we
considered its internal control, including control activities for
safeguarding securities, in order to determine our auditing procedures for
the purpose of expressing our opinion on the financial statements and to
comply with the requirements of Form N-SAR, not to provide assurance on
internal control.
The management of Dreyfus Institutional Money Market Fund, Inc. is
responsible for establishing and maintaining internal control. In fulfilling
this responsibility, estimates and judgments by management are required to
assess the expected benefits and related costs of controls. Generally,
controls that are relevant to an audit pertain to the entity's objective of
preparing financial statements for external purposes that are fairly
presented in conformity with generally accepted accounting principles. Those
controls include the safeguarding of assets against unauthorized
acquisition, use or disposition.
Because of inherent limitations in internal control, error or fraud may
occur and not be detected. Also, projection of any evaluation of internal
control to future periods is subject to the risk that it may become
inadequate because of changes in conditions or that the effectiveness of the
design and operation may deteriorate.
Our consideration of internal control would not necessarily disclose all
matters in internal control that might be material weaknesses under
standards established by the American Institute of Certified Public
Accountants. A material weakness is a condition in which the design or
operation of one or more of the internal control components does not reduce
to a relatively low level the risk that misstatements caused by error or
fraud in amounts that would be material in relation to the financial
statements being audited may occur and not be detected within a timely
period by employees in the normal course of performing their assigned
functions. However, we noted no matters involving internal control and its
operation, including controls for safeguarding securities, that we consider
to be material weaknesses as defined above at December 31, 1999.
This report is intended solely for the information and use of management,
the Board of Directors of Dreyfus Institutional Money Market Fund, Inc., 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
February 7, 2000
