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                            April 19, 2022

       Ken Song, M.D.
       President and Chief Executive Officer
       RayzeBio, Inc.
       5505 Morehouse Drive, Suite 300
       San Diego, CA 92121

                                                        Re: RayzeBio, Inc.
                                                            Amendment No. 1 to
Draft Registration Statement on Form S-1
                                                            Submitted April 5,
2022
                                                            CIK No. 0001825367

       Dear Mr. Song:

             We have reviewed your amended draft registration statement and
have the following
       comments. In some of our comments, we may ask you to provide us with
information so we
       may better understand your disclosure.

              Please respond to this letter by providing the requested
information and either submitting
       an amended draft registration statement or publicly filing your
registration statement on
       EDGAR. If you do not believe our comments apply to your facts and
circumstances or do not
       believe an amendment is appropriate, please tell us why in your
response.

             After reviewing the information you provide in response to these
comments and your
       amended draft registration statement or filed registration statement, we
may have additional
       comments.

       Amendment No. 1 to Draft Registration Statement on Form S-1

       Company overview, page 1

   1.                                                   We note your disclosure
that you are "initiating a Phase 1 clinical trial for RYZ101 in
                                                        patients with GEP-NETs
in the first half of 2022 and plan to file an IND for RYZ101 in
                                                        patients with SCLC in
the second half of 2022." Please clarify here and throughout the
                                                        registration statement
whether you have an IND for RYZ101 in patients with GEP-NETs
                                                        and, if so, the
jurisdiction where your Phase 1 clinical trials will take place.
       Our amended and restated certificate of incorporation that will be
effective..., page 81

   2.                                                   We note your revised
disclosure on page 81 that you would "expect to vigorously assert
                                                        the validity and
enforceability of the exclusive forum provisions of [y]our amended and
 Ken Song, M.D.
RayzeBio, Inc.
April 19, 2022
Page 2
       restated certificate of incorporation. This may require significant
additional costs
       associated with resolving such action in other jurisdictions and there
can be no assurance
       that the provisions will be enforced by a court in those other
jurisdictions." Please clarify
       that such "significant additional costs" could be borne by investors.
Intellectual Property, page 133

3.     Please disclose the jurisdictions in which you have filed your two
pending international
       patent applications pursuant to the Patent Cooperation Treaty.
       You may contact Gary Newberry at 202-551-3761 or Kevin Vaughn at
202-551-3494 if
you have questions regarding comments on the financial statements and related
matters. Please
contact Joshua Gorsky at 202-551-7836 or Celeste Murphy at 202-551-3257 with
any other
questions.



                                                              Sincerely,
FirstName LastNameKen Song, M.D.
                                                              Division of
Corporation Finance
Comapany NameRayzeBio, Inc.
                                                              Office of Life
Sciences
April 19, 2022 Page 2
cc:       Terren J. O'Connor, Esq.
FirstName LastName