As filed with the Securities and Exchange Commission on March 21, 2013
================================================================================
                                            1933 Act Registration No. 333-174332
                                             1940 Act Registration No. 811-22559

                                 UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                   FORM N-1A

REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933                     [ ]
Post-Effective Amendment No. __                                             [ ]
Post-Effective Amendment No. 30                                             [X]
                                     and/or
REGISTRATION STATEMENT UNDER THE INVESTMENT COMPANY ACT OF 1940             [ ]
Amendment No. 32                                                            [X]


                      FIRST TRUST EXCHANGE-TRADED FUND IV
               (Exact name of registrant as specified in charter)
                       120 East Liberty Drive, Suite 400
                            Wheaton, Illinois 60187
              (Address of Principal Executive Offices) (Zip Code)


       REGISTRANT'S TELEPHONE NUMBER, INCLUDING AREA CODE: (800) 621-1675

                       W. Scott Jardine, Esq., Secretary
                      First Trust Exchange-Traded Fund IV
                           First Trust Advisors L.P.
                       120 East Liberty Drive, Suite 400
                            Wheaton, Illinois 60187
                    (Name and Address of Agent for Service)

                                    Copy to:
                               Eric F. Fess, Esq.
                             Chapman and Cutler LLP
                             111 West Monroe Street
                            Chicago, Illinois 60603


It is proposed that this filing will become effective (check appropriate box):

[X] immediately upon filing pursuant to paragraph (b)
[ ] on ___________ pursuant to paragraph (b)
[ ] 60 days after filing pursuant to paragraph (a)(1)
[ ] on (date) pursuant to paragraph (a)(1)
[ ] 75 days after filing pursuant to paragraph (a)(2)
[ ] on (date) pursuant to paragraph (a)(2) of Rule 485.

If appropriate, check the following box:

[ ] this post-effective amendment designates a new effective date for a
    previously filed post-effective amendment.


      This Registration Statement relates to First Trust North American Energy
Infrastructure Fund, a series of the Registrant.





                                   SIGNATURES

      Pursuant to the requirements of the Securities Act of 1933 and the
Investment Company Act of 1940, the Registrant certifies that it meets all of
the requirements for effectiveness of this Registration Statement under Rule
485(b) under the Securities Act of 1933 and has duly caused this Registration
Statement to be signed on its behalf by the undersigned, duly authorized in the
City of Wheaton, and State of Illinois, on the 21st day of March, 2013.

                                          FIRST TRUST EXCHANGE-TRADED FUND IV



                                          By: /s/ Mark R. Bradley
                                              --------------------------------
                                              Mark R. Bradley, President and
                                              Chief Executive Officer


      Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed below by the following persons in the
capacities and on the date indicated:



                                                                        
SIGNATURE                               TITLE                                 DATE

/s/ Mark R. Bradley                     President and Chief Executive         March 21, 2013
--------------------------------------- Officer
    Mark R. Bradley


/s/ James M. Dykas                      Treasurer, Chief Financial Officer    March 21, 2013
--------------------------------------- and Chief Accounting Officer
    James M. Dykas

                                                         )
James A. Bowen*                                  Trustee )
                                                         )
                                                         )
Richard E. Erickson*                             Trustee )
                                                         )
                                                         )
Thomas R. Kadlec*                                Trustee )                    BY: /s/ W. Scott Jardine
                                                         )                        ------------------------------
                                                         )                            W. Scott Jardine
Robert F. Keith*                                 Trustee )                            Attorney-In-Fact
                                                         )                            March 21, 2013
                                                         )
Niel B. Nielson*                                 Trustee )
                                                         )


*  Original powers of attorney authorizing James A. Bowen, W. Scott Jardine,
   Mark R. Bradley, Eric F. Fess and Kristi A. Maher to execute Registrant's
   Registration Statement, and Amendments thereto, for each of the trustees of
   the Registrant on whose behalf this Registration Statement is filed, were
   previously executed, filed as an exhibit and are incorporated by reference
   herein.





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