CHAPMAN AND CUTLER LLP
                             111 WEST MONROE STREET
                                CHICAGO, IL 60603


                                  May 10, 2018


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


          Re: Guggenheim Defined Portfolios, Series 1758 (the "Fund")
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Ladies and Gentlemen:

     Enclosed please find a copy of Amendment No. 1 to the Registration
Statement on Form S-6 for the registration under the Securities Act of 1933 of
units representing the ownership of interests in the subject Fund. This
Amendment No. 1 to the Registration Statement is filed on May 10, 2018, on
behalf of Guggenheim Funds Distributors, LLC (the "Sponsor").

     Inasmuch as the Fund is not yet operative, no filings have been required
under any of the acts administered by the Commission. Therefore, for purposes of
Securities Act Release No. 5196 there are no delinquencies to be reported or
other references to be made to filings under the 1934 Act.

     No notification of registration or Registration Statement under the
Investment Company Act of 1940 is currently being submitted to the Commission,
as the filings under the 1940 Act (File No. 811-03763) are intended to apply not
only to that series of the Fund, but to all "subsequent series" as well.

     The Fund is expected to be comprised of the following unit investment
trust: Core Four 60/40 Retirement Portfolio, Series 3 (the "Trust"). The Trust
will invest in a portfolio of common stocks, real estate investment trusts and
shares of exchange-traded funds ("ETFs"). As the ETFs in which the Trust will
invest is structured as an open-end management company or unit investment trust,
the Trust is not eligible to go automatically effective in reliance on Rule 487
under the Securities Act of 1933. The Trust may not rely on Rule 487 because
paragraph (b)(1) of Rule 487 requires that reliance upon the rule is conditioned
upon the registrant not engaging in the business of investing in open-end funds.
Absent paragraph (b)(1) of Rule 487, it would be our opinion that the
Registration Statement would not contain disclosures which would render it
ineligible to become effective pursuant to Rule 487.

     We are advised that the Sponsor proposes to deposit securities and to
activate the subject Fund on May 16, 2018

     In the event that you may have any questions with regard hereto or if there
is any way which we can be of assistance, please do not hesitate to telephone
Eric F. Fess collect at (312) 845-3781 or Morrison C. Warren at (312) 845-3484.

                                                               Very truly yours,

                                                      /s/ Chapman and Cutler LLP
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                                                          CHAPMAN AND CUTLER LLP