Guggenheim Funds Distributors, Inc.
                            2455 Corporate West Drive
                              Lisle, Illinois 60532


                                  June 3, 2011


Securities and Exchange Commission
100 F Street, N.E.
Washington, DC 20549


                  Re: Guggenheim Defined Portfolios, Series 788
                               File No. 333-173875


Ladies/Gentlemen:

   The undersigned, Guggenheim Defined Portfolios, Series 788 (the "Trust"), by
Guggenheim Funds Distributors, Inc., as the sponsor and depositor of the Trust
and of the units covered by the subject Registration Statement, pursuant to the
provisions of Rule 461 of the General Rules and Regulations of the Securities
and Exchange Commission under the Securities Act of 1933, hereby respectfully
requests that the Securities and Exchange Commission consent to the filing of
the amendment to the Registration Statement and grant acceleration of the
effectiveness of said Registration Statement, as amended, so that the same may
become effective as early as practicable on June 8, 2011 or as soon thereafter
as possible.

Very truly yours,

Guggenheim Defined Portfolios, Series 788

By: Guggenheim Funds Distributors, Inc.


By: /s/ KEVIN ROBINSON
----------------------
Kevin Robinson

Senior Managing Director,
General Counsel and Secretary