United States securities and exchange commission logo

                       March 8, 2021

       Christopher Anzalone
       Chief Executive Officer
       Arrowhead Pharmaceuticals, Inc.
       177 E. Colorado Blvd, Suite 700
       Pasadena, California 91105

                                                        Re: Arrowhead
Pharmaceuticals, Inc.
                                                            Form 10-K for the
fiscal year ended September 30, 2020
                                                            Filed November 23,
                                                            File No. 001-38042

       Dear Mr. Anzalone:

              We have completed our review of your filing. 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.


                       Division of Corporation Finance

                       Office of Life Sciences