EXHIBIT 11

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

February 23, 2006

Rydex Series Funds
9601 Blackwell Road
Suite 500
Rockville, MD 20850

Re:   OPINION OF COUNSEL  RELATING TO THE  REGISTRATION  STATEMENT FILED ON FORM
      N-14 UNDER THE SECURITIES ACT OF 1933

Ladies and Gentlemen:

We  refer  to  the  registration  statement  on  Form  N-14  (the  "Registration
Statement")  of Rydex  Series Funds (the  "Trust"),  relating to the transfer of
substantially  all the assets and stated  liabilities of Rydex Capital  Partners
SPhinX Fund (the "Selling Fund"), in exchange for shares of the Trust's Absolute
Return Strategies Fund (the "Acquiring  Fund"),  followed by the distribution of
such shares (the "Acquiring Fund's Shares"), in exchange for such Selling Fund's
shares (the "Reorganization").

We have been requested by the Trust to furnish this opinion as an exhibit to the
Registration Statement. With your permission,  all assumptions and statements of
reliance  herein  have  been  made  without  any  independent  investigation  or
verification on our part except to the extent otherwise expressly stated, and we
express no  opinion  with  respect to the  subject  matter or  accuracy  of such
assumptions or items relied upon.

In connection with this opinion, we have reviewed,  among other things, executed
copies of the following documents:

      (a)   a certificate  of the State of Delaware as to the existence and good
            standing of the Trust;

      (b)   copies of the Trust's  Agreement and Declaration of Trust and of all
            amendments and all supplements thereto (the "Declaration of Trust");

      (c)   a certificate executed by Joanna M. Haigney, Secretary of the Trust,
            certifying to and  attaching  copies of the Trust's  Declaration  of
            Trust and By-Laws,  and certain  resolutions adopted by the Board of
            Trustees of the Trust authorizing the issuance of the shares; and

      (d)   a printer's proof of the Registration Statement.



In our  capacity as counsel to the Trust,  we have  examined  the  originals  or
certified,   conformed  or  reproduced   copies  of  all  records,   agreements,
instruments  and documents as we have deemed  relevant or necessary as the basis
for the opinion hereinafter expressed. In all such examinations, we have assumed
the legal capacity of all natural persons executing  documents,  the genuineness
of all signatures, the authenticity of all original or certified copies, and the
conformity  to original or  certified  copies of all copies  submitted  to us as
conformed or reproduced copies. As to various questions of fact relevant to such
opinion,  we have relied upon, and assume the accuracy of, certificates and oral
or written statements of public officials and officers or representatives of the
Trust. We have assumed that the Registration  Statement,  as filed with the U.S.
Securities and Exchange  Commission,  will be in  substantially  the form of the
printer's proof referred to in paragraph (d) above.

      Based upon, and subject to, the  limitations  set forth herein,  we are of
      the opinion that the issuance of the Acquiring  Fund's Shares by the Trust
      has been duly and legally  authorized by all appropriate  action and, upon
      delivery  thereof and payment therefor in accordance with the Registration
      Statement,  the  Acquiring  Fund's  Shares,  when issued,  will be legally
      issued,  fully  paid and  non-assessable  under  the laws of the  State of
      Delaware.

We have not reviewed the securities laws of any state or territory in connection
with the  proposed  offering of the  Acquiring  Fund's  Shares and we express no
opinion as to the legality of any offer or sale of the  Acquiring  Fund's Shares
under any such state or territorial securities laws.

This opinion is intended  only for your use in  connection  with the offering of
the Acquiring Fund's Shares and may not be relied upon by any other person.

We  hereby  consent  to  the  filing  of  this  opinion  as an  exhibit  to  the
Registration  Statement on Form N-14. In giving this consent,  we do not concede
that we are in the category of persons whose consent is required under Section 7
of the Securities Act of 1933, as amended.

Very truly yours,


/s/ Morgan, Lewis & Bockius LLP