1775 I Street, N.W.

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+1  202  261  3300  Main

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www.dechert.com

JULIEN BOURGEOIS

julien.bourgeois@dechert.com

+1 202 261 3451  Direct

+1 202 261 3151  Fax

November 28, 2011

VIA EDGAR

U.S. Securities and Exchange Commission

100 F Street, NE

Washington, D.C.  20549

Re: Security Mid Cap Growth Fund

(File Nos. 2-32791 and 811-01316)

Ladies and Gentlemen:

On behalf of Security Mid Cap Growth Fund (the “Corporation”), attached for filing via the EDGAR system pursuant to Rule 485(a)(1) under the Securities Act of 1933, as amended, is Post-Effective Amendment No. 69 to the Corporation’s registration statement on Form N-1A.  This filing is being made for the purpose of registering an institutional share class for the Mid Cap Growth Fund, a series of the Corporation.

No fee is required in connection with this filing.  Should you have any questions regarding this filing, please contact the undersigned at 202.261.3451.

Sincerely,

/s/ Julien Bourgeois

Julien Bourgeois

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