SecProbe.io

CORRESP
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  ROPES & GRAY LLP

191 North Wacker Drive, 32nd Floor

Chicago, IL 60606

WWW.ROPESGRAY.COM

November 21,2024 Rita Rubin

T +1 312-845-1241

Rita.Rubin@ropesgray.com

VIA EDGAR

U.S. Securities and Exchange Commission

100 F Street, NE

Washington, DC 20549

Re: Calamos ETF Trust (“Registrant” or “Trust”) on behalf of four of its series,

                                                               Calamos Bitcoin 100% Protection Strategy (1 yr) ETF — Month TBD 1

                                                               Calamos Bitcoin 100% Protection Strategy (1 yr) ETF — Month TBD 2

                                                               Calamos Bitcoin 100% Protection Strategy (1 yr) ETF — Month TBD 3

                                                               Calamos Bitcoin 100% Protection Strategy (1 yr) ETF — Month TBD 4

                                                               (each, a “Fund” and collectively, the “Funds”)

                                                               (File Nos. 333-191151 and 811-22887)

Ladies and Gentlemen:

On
behalf of the Registrant, in connection with amendments to four series of Calamos ETF Trust, we are filing today by electronic submission
via EDGAR pursuant to Rule 485(a)(1) a post-effective amendment (Post-Effective Amendment No. 48) to the Trust’s registration
statement on Form N-1A a copy of each of the following:

 1. Prospectuses relating to the four ETFs (the “Prospectuses”); and

 2. Statement of additional information relating to the four ETFs (the “SAI”).

Except
as indicated below, the disclosure for each of the ETFs is based on and substantially similar to disclosure previously reviewed by the
staff of the U.S. Securities and Exchange Commission (“SEC”) in the Registrant’s filing on Form N-1A (SEC Accession
Number 0001104659-24-102657) filed on September 25, 2024 pursuant to Rule 485(b) of the Securities Act of 1933, as amended, (the
 “Securities Act”) (the “Precedent Filing”).

The
Registrant requests selective review of Post-Effective Amendment No. 48 in accordance with the SEC’s release on selective
review, Revised Procedures For Processing Registration Statements, Post-Effective Amendments and Preliminary Proxy Materials Filed
by Registered Investment Companies, Investment Company Act Release No. 13768 (February 15, 1984).

    - 2 -

Prospectuses

The
Precedent Filing registered the following ETFs which had the following characteristics:

    Fund Name
    Launch Date
    Start of Outcome Period

    Calamos Bitcoin Structured Alt Protection ETF — Month TBD 1
    TBD
    TBD

    Calamos Bitcoin Structured Alt Protection ETF — Month TBD 2
    TBD
    TBD

    Calamos Bitcoin Structured Alt Protection ETF — Month TBD 3
    TBD
    TBD

    Calamos Bitcoin Structured Alt Protection ETF — Month TBD 4
    TBD
    TBD

The Registrant requests selective review of the Prospectuses listed
below. The Prospectuses are substantially similar to the prospectuses in the Precedent Filing. The primary differences are the ETF names,
launch dates, the investment objective and strategy with respect to the underlying ETP(s) and index, the types of options the Fund may
use to implement its strategy and the dates on which the respective outcome periods begin and reset for each of the four ETFs:1

    Fund Name per Upcoming

Pre-Effective Registration

 Statement Filing
    Launch Date per

 Upcoming Pre-Effective

 Registration Statement

 Filing
    Outcome Period Reset dates per

 Upcoming Pre-Effective

 Registration Statement Filing

    Calamos Bitcoin 100% Protection Strategy (1 yr) ETF — Month TBD 1
    TBD
    TBD

    Calamos Bitcoin 100% Protection Strategy (1 yr) ETF — Month TBD 2
    TBD
    TBD

    Calamos Bitcoin 100% Protection Strategy (1 yr) ETF — Month TBD 3
    TBD
    TBD

    Calamos Bitcoin 100% Protection Strategy (1 yr) ETF — Month TBD 4
    TBD
    TBD

SAI

The
Registrant requests selective review of the SAI, which is being filed with language that is substantially similar to the Precedent
Filing. The differences in the disclosure in this SAI is that the new SAI will contain new ETF names, launch dates, the investment objective
and strategy with respect to the underlying ETP(s) and index, the types of options the Fund may use to implement its strategy and the
dates on which the outcome periods begin and reset.

1
As explained in more detail in the Prospectus of each series, the outcome period is an approximate one-year period over which each Fund
seeks to produce a targeted result. The Funds will not terminate after the conclusion of the Outcome Period. After the conclusion of the
Outcome Period, another will begin.

    - 3 -

Please direct any questions you may have with respect to this filing
to me at (312) 845-1241.

    Very
    truly yours,

    /s/
    Rita Rubin

    Rita
    Rubin, Esq.

    cc:
    John P. Calamos, Sr.

    Erik D. Ojala, Esq.

    J. Christopher Jackson, Esq.

    Susan L. Schoenberger, Esq.

    Paulita Pike, Esq.

    Elizabeth Madsen, Esq.

    C. Lawrence Zmerega, Esq.

    Daniel Koningisor, Esq.