SecProbe.io

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DRAFT

Morgan, Lewis & Bockius LLP
1111 Pennsylvania Ave., NW
Washington, DC 20004

LAURA E. FLORES*
202.739.5684
lflores@morganlewis.com
* Admitted in Florida only

May XX, 2005

VIA EDGAR CORRESPONDENCE

Mr. Christian T. Sandoe
U.S. Securities and Exchange Commission
Judiciary Plaza
450 Fifth Street, N.W.
Washington, DC  20549

Re:      RYDEX SERIES FUNDS (THE "TRUST") - POST EFFECTIVE AMENDMENT NO. 56
         (FILE NOS. 333-59692 AND 811-07584)

Dear Mr. Sandoe:

This letter responds to your comments to the Trust's Post-Effective Amendment
No. 56, filed on March 10, 2005 for the purpose of introducing the Strengthening
Dollar Fund, Weakening Dollar Fund, and Commodities Fund (each a "Fund" and
together, the "Funds") into the Trust. The following summarizes your comments,
and our response to those comments. Unless otherwise noted, capitalized terms
have the same meaning as contained in the Funds' Prospectus and/or Statement of
Additional Information (SAI).

1.       COMMENT. Please include disclosure concerning the Strengthening Dollar
         and Weakening Dollar Funds' policy to invest at least 80% of the value
         of their assets in instruments suggested by each Fund's name.

         RESPONSE. Section 35(d) of the Investment Company Act of 1940 makes it
         unlawful for a fund to adopt as part of its name any word which the
         Commission finds, by rule regulation or order, to be materially
         deceptive or misleading. Rule 35d-1, as adopted by the Commission,
         states, in pertinent part, that names suggesting investment in certain
         investments are misleading in the absence of the fund adopting a policy
         to invest at least 80% of its net assets in the particular type of
         investment. We do not believe that Rule 35d-1 is applicable to the
         Strengthening Dollar and Weakening Dollar Funds because the use of the
         word "dollar" in the name of each Fund does not suggest a focus on a
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         particular type of investment. In fact, we are unable to speculate as
         to what type of investment the staff might believe is suggested by use
         of the word "dollar." Further, we believe that the use of "dollar" in
         the Funds' names is neither deceptive nor does it raise the concerns
         discussed in the Release adopting Rule 35d-1.1 The Funds' names would
         not "lead a reasonable investor to conclude that the Funds invest in a
         manner that is inconsistent with the Funds' intended investments or the
         risk of those investments."2 Therefore, we have not included disclosure
         concerning an 80% policy for the Funds. The Strengthening Dollar and
         Weakening Dollar Funds' "Principal Investment Strategy" is disclosed as
         follows:

         Strengthening Dollar Fund:

         The Strengthening Dollar Fund employs as its investment strategy a
         program of investing in derivative instruments, such as index swaps,
         futures contracts and options on securities, and futures contracts.
         Investing in derivative instruments enables the Fund to pursue its
         objective without investing directly in the securities included in the
         underlying index, or in the same proportion that those securities are
         represented in the underlying index. On a day-to-day basis, the
         Strengthening Dollar Fund holds U.S. Government securities or cash
         equivalents to collateralize these futures and options contracts. The
         Strengthening Dollar Fund also may enter into repurchase agreements.
         The US Dollar Index is a broad based, diversified index representing an
         investment in the U.S. Dollar (USD). The New York Board of Trade
         determines the value of the US Dollar Index by averaging the exchange
         rates between the USD and the Euro, Japanese Yen, British Pound,
         Canadian Dollar, Swedish Krona, and Swiss Franc.

         Weakening Dollar Fund:

         The Weakening Dollar Fund employs as its investment strategy a program
         of engaging in short sales of securities and investing in derivative
         instruments, such as index swaps, futures contracts and options on
         securities, and futures contracts. Engaging in short sales and
         investing in derivative instruments enables the Fund to pursue its
         objective without investing directly in the securities included in the
         underlying index, or in the same proportion that those securities are
         represented in the underlying index. On a day-to-day basis, the
         Weakening Dollar Fund holds U.S. Government securities or cash
         equivalents to collateralize these futures and options contracts. The
         Weakening Dollar Fund also may enter into repurchase agreements. The US
         Dollar Index is a broad based, diversified index representing an
         investment in the U.S. Dollar (USD). The New York Board of Trade
         determines the value of the US Dollar Index by averaging the exchange
         rates between the USD and the Euro, Japanese Yen, British Pound,
         Canadian Dollar, Swedish Krona, and Swiss Franc.

----------
1 INVESTMENT COMPANY NAMES, Investment Company Act Rel. No. 24828
- (Jan. 17, 2001).

2 ID. at p.8.
-

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2.       COMMENT. Please include disclosure concerning the Commodities Fund's
         policy to invest at least 80% of the value of its assets in commodity
         investments as suggested by the Fund's name on page 9 of the
         Prospectus.

         RESPONSE. We have revised the language under the Fund's "Principal
         Investment Strategy" as follows:

         "The Commodities Fund seeks 100% (but at all times at least 80%)
         exposure to the performance of the commodities markets. This is a
         non-fundamental policy that can be changed by the Commodities Fund upon
         60 days' prior notice to shareholders. The Fund will seek to gain
         exposure to the commodity markets by investing in commodity-linked
         derivative instruments, including swap agreements, commodity options,
         futures, options on futures and commodity-linked notes. Investing in
         derivative instruments enables the Fund to pursue its objective without
         investing directly in physical commodities. It is anticipated that the
         Fund's investment exposure will tend to be heavily weighted toward oil
         and other energy-related commodities. On a day-to-day basis, the Fund
         holds U.S. Government securities or cash equivalents to collateralize
         these futures and options contracts."

3.       COMMENT. Please revise the "Currency Risk" discussion for the
         Strengthening Dollar and Weakening Dollar Funds to more accurately
         explain the Funds' exposure to foreign currencies.

         RESPONSE. We have revised the "Currency Risk" discussion for the
         Strengthening Dollar and Weakening Dollar Funds on pages 5 and 7 of the
         Prospectus as follows:

         Strengthening Dollar Fund:

         "CURRENCY RISK - The Fund's exposure to the U.S. Dollar Index subjects
         the Fund to the risk that the foreign currencies will appreciate in
         value relative to the U.S. Dollar. Currency rates in foreign countries
         may fluctuate significantly over short periods of time for a number of
         reasons, including changes in interest rates and the imposition of
         currency controls or other political developments in the U.S. or
         abroad."

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         Weakening Dollar Fund:

         "CURRENCY RISK - The Fund's exposure to the U.S. Dollar Index subjects
         the Fund to the risk that the U.S. Dollar will appreciate in value
         relative to foreign currencies. Currency rates in foreign countries may
         fluctuate significantly over short periods of time for a number of
         reasons, including changes in interest rates and the imposition of
         currency controls or other political developments in the U.S. or
         abroad."

4.       COMMENT. Please revise the "Energy Sector Risk" discussion on page 9 of
         the Prospectus to explain how energy sector commodities may
         underperform the market as a whole.

         RESPONSE. While we believe that the "Energy Sector Risk" discussion
         currently satisfies the requirements of Item 2, we have revised the
         discussion as follows (new language appears in bold for the purposes of
         this correspondence only):

         "Energy Sector Concentration Risk - The risk that energy sector
         commodities that the Fund purchases will underperform the market as a
         whole EITHER BY DECLINING IN VALUE OR FAILING TO PERFORM AS WELL. To
         the extent that the Fund's investments are concentrated in the same
         economic sector, the Fund is subject to legislative or regulatory
         changes, adverse market conditions and/or increased competition
         affecting that economic sector. The prices of energy sector commodities
         may fluctuate widely due to changes in value, which depend largely on
         the price and supply of energy fuels, international political events
         relating to oil producing countries, energy conservation, the success
         of exploration projects, and tax and other governmental regulatory
         policies."

5.       COMMENT. Please provide a brief explanation of each portfolio manager's
         role on the management team on page 25 of the Prospectus.

         RESPONSE. We have revised the first paragraph under "Portfolio
         Management" as follows:

         "Each Fund is managed by a team of investment professionals. The
         following portfolio managers are jointly and primarily responsible for
         the day-to-day management of the Funds. Each of the following portfolio
         managers is a member of Rydex's Investment Leadership Team and together
         they share final portfolio management decision-making authority."

6.       COMMENT. Please provide more specific disclosure with regard to the
         information the Board of Trustees considered and their findings prior
         to their approval of the investment advisory agreement.

         RESPONSE. We have revised the fourth paragraph of the "Board
         Considerations in Approving the Advisory Agreement" section located on
         page 21 of the SAI as follows:

         "Based on the Board's deliberations and its evaluation of the
         information described above, the Board, including all of the
         independent trustees, agreed that the Advisor had provided high quality
         services to the Rydex family of Funds in respect to such matters as
         managing the Funds' portfolios in a manner consistent with the Funds'
         respective investment objectives, as well as providing transfer agency
         services, fund accounting services and other services to Fund investors
         in a manner that meets the needs of investors. In addition, the Board
         found that the fees charged by the Advisor for the

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         services to be provided to the Funds were reasonable in light of the
         costs of the services, the profitability of the Advisor, and the fees
         charged by advisers to other comparable funds. As a result of these
         findings, the Board unanimously: (a) concluded that terms of the
         investment advisory agreement are fair and reasonable; (b) concluded
         that the Advisor's fees are reasonable in light of the services that
         the Advisor provides to the Trust; and (c) agreed to renew the
         investment advisory agreement for the Funds."

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I hereby acknowledge on behalf of the Rydex Series Funds (the "Trust") that: (i)
the Trust is responsible for the adequacy and accuracy of the disclosure in its
registration statement; (ii) SEC staff comments or changes to disclosure in
response to staff comments in the registration statement reviewed by the staff
do not foreclose the SEC from taking any action with respect to the registration
statement; and (iii) the Trust may not assert SEC staff comments as a defense in
any proceeding initiated by the SEC or any person under the federal securities
laws of the United States.

If you have any additional questions or comments, please do not hesitate to
contact either John McGuire at 202.739.5654 or me at 202.739.5684.

Sincerely,

Laura E. Flores

cc: W. John McGuire, Esq.
         John M. Ford, Esq.
         Joanna Haigney

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