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SIGNATURE STEVE LEMIRE
TITLE SECRETARY
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THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED
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<ACCUMULATED-NET-GAINS> (3,959)
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 5,218
<NET-ASSETS> 36,837
<DIVIDEND-INCOME> 29
<INTEREST-INCOME> 83
<OTHER-INCOME> 0
<EXPENSES-NET> 693
<NET-INVESTMENT-INCOME> (581)
<REALIZED-GAINS-CURRENT> (2,556)
<APPREC-INCREASE-CURRENT> 4,779
<NET-CHANGE-FROM-OPS> 1,642
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 2,700
<NUMBER-OF-SHARES-REDEEMED> (2,492)
<SHARES-REINVESTED> 0
<NET-CHANGE-IN-ASSETS> 6,104
<ACCUMULATED-NII-PRIOR> 0
<ACCUMULATED-GAINS-PRIOR> (1,403)
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 229
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 693
<AVERAGE-NET-ASSETS> 38,192
<PER-SHARE-NAV-BEGIN> 12.28
<PER-SHARE-NII> (.21)
<PER-SHARE-GAIN-APPREC> 1.52
<PER-SHARE-DIVIDEND> 0
<PER-SHARE-DISTRIBUTIONS> 0
<RETURNS-OF-CAPITAL> 0
<PER-SHARE-NAV-END> 13.59
<EXPENSE-RATIO> 1.81
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED
FROM DECEMBER 31, 1997 ANNUAL REPORT AND IS QULAIFIED
IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
<SERIES>
<NUMBER> 3
<NAME> OBERWEIS MID-CAP PORTFOLIO
<MULTIPLIER> 1,000
<S> <C>
<PERIOD-TYPE> 12-MOS
<FISCAL-YEAR-END> DEC-31-1997
<PERIOD-START> JAN-01-1997
<PERIOD-END> DEC-31-1997
<INVESTMENTS-AT-COST> 5,623
<INVESTMENTS-AT-VALUE> 6,205
<RECEIVABLES> 129
<ASSETS-OTHER> 48
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 6,382
<PAYABLE-FOR-SECURITIES> 0
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 35
<TOTAL-LIABILITIES> 35
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 5,990
<SHARES-COMMON-STOCK> 604
<SHARES-COMMON-PRIOR> 608
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> (225)
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 582
<NET-ASSETS> 6,347
<DIVIDEND-INCOME> 8
<INTEREST-INCOME> 5
<OTHER-INCOME> 0
<EXPENSES-NET> 133
<NET-INVESTMENT-INCOME> (120)
<REALIZED-GAINS-CURRENT> 49
<APPREC-INCREASE-CURRENT> 347
<NET-CHANGE-FROM-OPS> 276
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0
<DISTRIBUTIONS-OF-GAINS> (211)
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 264
<NUMBER-OF-SHARES-REDEEMED> (388)
<SHARES-REINVESTED> 18
<NET-CHANGE-IN-ASSETS> (948)
<ACCUMULATED-NII-PRIOR> 0
<ACCUMULATED-GAINS-PRIOR> (63)
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 27
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 164
<AVERAGE-NET-ASSETS> 6,647
<PER-SHARE-NAV-BEGIN> 10.29
<PER-SHARE-NII> (.19)
<PER-SHARE-GAIN-APPREC> .76
<PER-SHARE-DIVIDEND> 0
<PER-SHARE-DISTRIBUTIONS> (.35)
<RETURNS-OF-CAPITAL> 0
<PER-SHARE-NAV-END> 10.51
<EXPENSE-RATIO> 2.00
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0
</TABLE>
Report of Internal Control
The Board of Trustees
The Oberweis Funds
In planning and performing our audit of the financial statements of each of
The Oberweis Funds, consisting of the Oberweis Emerging Growth Portfolio, the
Oberweis Micro-Cap Portfolio, and the Oberweis Mid-Cap Portfolio, for the year
ended December 31, 1997, we considered their 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 the internal control.
The management of The Oberweis Funds 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 control. 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, errors or irregularities
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 the internal control would not necessarily disclose all
matters in the 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 of risk that errors or irregularities 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 the internal control and its operation, including controls for
safeguarding securities, that we consider to be material weaknesses as defined
above as of December 31, 1997.
This report is intended solely for the information and use of the board of
trustees and management of The Oberweis Funds and the Securities and Exchange
Commission.
ERNST & YOUNG LLP
Chicago, Illinois
January 26, 1998
