United States securities and exchange commission logo

                               June 15, 2020

       Laura A. Francis
       Chief Operating Officer & Chief Financial Officer
       SI-BONE, Inc.
       471 El Camino Real, Suite 101
       Santa Clara, CA 95050

                                                        Re: SI-BONE, Inc.
                                                            Form 10-K for the
Fiscal Year Ended December 31, 2019
                                                            Filed March 11,
                                                            Form 10-Q for the
Fiscal Quarter Ended March 31, 2020
                                                            Filed May 5, 2020
                                                            File No. 001-38701

       Dear Ms. Francis:

              We have reviewed your filings and have the following comment. In
some of our
       comments, we may ask you to provide us with information so we may better
understand your

              Please respond to this comment within ten business days by
providing the requested
       information or advise us as soon as possible when you will respond. If
you do not believe our
       comment applies to your facts and circumstances, please tell us why in
your response.

                                                        After reviewing your
response to this comment, we may have additional comments.

       Form 10-Q for the Fiscal Quarter Ended March 31, 2020


   1.                                                   We note the
certifications provided in Exhibits 31.1 and 31.2 do not include paragraph
                                                        4(b) and the
introductory language in paragraph 4 referring to internal control over
                                                        financial reporting
after the end of the transition period that allows these omissions. Please
                                                        amend the filing to
provide revised certifications. You may file an abbreviated amendment
                                                        that is limited to the
cover page, explanatory note, signature page and paragraphs 1, 2, 4
                                                        and 5 of the
certification. Refer to Exchange Act Rule 13a-14(a) and Item 601(b)(31) of
                                                        Regulation S-K.
 Laura A. Francis
June 15, 2020
Page 2

        We remind you that the company and its management are responsible for
the accuracy
and adequacy of their disclosures, notwithstanding any review, comments, action
or absence of
action by the staff.

        You may contact Gary Newberry at (202) 551-3761 or Kevin Kuhar,
Accounting Branch
Chief, at (202) 551-3662 with any questions.

FirstName LastNameLaura A. Francis                        Sincerely,
Comapany NameSI-BONE, Inc.
                                                          Division of
Corporation Finance
June 15, 2020 Page 2                                      Office of Life
FirstName LastName