<DOCUMENT>
<TYPE>485BPOS
<SEQUENCE>1
<FILENAME>etf1_485b.txt
<DESCRIPTION>INTERACTIVE DATA
<TEXT>
     As filed with the Securities and Exchange Commission on August 2, 2017
================================================================================
                                            1933 Act Registration No. 333-125751
                                             1940 Act Registration No. 811-21774


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

                                   FORM N-1A

REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933                     [ ]
Pre-Effective Amendment No. __                                              [ ]
Post-Effective Amendment No. 98                                             [X]
                                     and/or
REGISTRATION STATEMENT UNDER THE INVESTMENT COMPANY ACT OF 1940             [ ]
Amendment No. 98                                                            [X]


                        FIRST TRUST EXCHANGE-TRADED FUND
               (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
                           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.


<PAGE>


      This Registration Statement relates to First Trust Dow 30 Equal Weight
ETF, a series of the Registrant.


<PAGE>


                                   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 2nd day of August, 2017.


                                             FIRST TRUST EXCHANGE-TRADED FUND

                                             By: /s/ James M. Dykas
                                             ----------------------------------
                                             James M. Dykas, 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

                         President and Chief Executive         August 2, 2017
/s/ James M. Dykas       Officer
----------------------
    James M. Dykas
                         Treasurer, Chief Financial Officer    August 2, 2017
/s/ Donald P. Swade      and Chief Accounting Officer
----------------------
    Donald P. Swade

                                          )
James A. Bowen*                   Trustee )
                                          )
                                          )
Richard E. Erickson*              Trustee )         BY: /s/ W. Scott Jardine
                                          )             ---------------------
                                          )             W. Scott Jardine
Niel B. Nielson *                 Trustee )             Attorney-In-Fact
                                          )             August 2, 2017
                                          )
                                          )
Thomas R. Kadlec*                 Trustee )
                                          )
                                          )
Robert F. Keith*                  Trustee )


*     Original powers of attorney authorizing James A. Bowen, W. Scott Jardine,
      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.


<PAGE>


                               INDEX TO EXHIBITS

      (101) Risk/return summary in interactive data format

</TEXT>
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