                             SECURITIES AND EXCHANGE COMMISSION  
                                     450 Fifth Street, NW
                                     Washington, DDC  20549

                        ------------------------------------------

                                          FORM 8-K
                                       CURRENT REPORT

                           Pursuant to Section 13 or 15(d) of the
                              Securities Exchange Act of 1934

                              For the Month of August, 2003

                          WAMU MORTGAGE PASS-THROUGH CERTIFICATES,
                                     SERIES:  2003-s7
                 (Exact name of the registrant as specified in charter)

                 Delaware              333-103345-15        94-2528990
               (State or other         (Commission          (IRS Employer
               jurisdiction of         File Number)         Identification
               Incorporation)                               Number)


                                   75 NORTH FAIRWAY DRIVE
                                   VERNON HILLS, IL  60061

                         (Address of principal executive offices)

                    Registrant's telephone number, including area code:

                                      (847) 549-6500



ITEM 5.C

     See Exhibit 99, the Distribution Report for the Month of August, 2003,
attached hereto.

ITEM 205497.

    FINANCIAL STATEMENTS, PRO FORMA FINANCIAL INFORMATION, AND EXHIBITS:


     EXHIBITS:

     99.   WaMu Mortgage Pass-Through Certificates,
          SERIES:  2003-s7, Monthly Distribution Report for August 2003.

                                SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant has duly caused this report to be signed on its behalf by the
undersigned hereunto duly authorized.

Dated:    August 18, 2003

                                  WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
                                              (Registrant)

                                              By:   /s/
                                                    ------------------
                                                    RICHIE MOORE
                                                    VICE PRESIDENT

FORM 8-K CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported):July 23, 2003

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

as Depositor and Master Servicer under a Pooling and Servicing Agreementdated as of July 1, 2003 providing for the issuance of

WaMu MORTGAGE PASS-THROUGH CERTIFICATES SERIES 2003-S7 (Exact name of Registrant as specified in its charter)

Delaware		333-103345-15		94-2528990
(State or other jurisdiction of incorporation)		(Commission File Number)		(I.R.S. Employer Identification No.)

1201 THIRD AVENUE, WMT 1706 SEATTLE, WASHINGTON 98101 (Address of principal executive offices and Zip Code)

Registrant's telephone number, including area code: (206) 377-8555

ITEM 7. Financial Statements, Pro Forma Financial Information and Exhibits.

The following exhibit is filed herewith:

7.1 Pooling and Servicing Agreement by and among Washington Mutual Mortgage Securities Corp., as Depositor and Master Servicer, Citibank, N.A., as Trustee, and Christiana Bank & Trust Company, as Delaware Trustee, dated as of July 1, 2003.

The definition of the Mortgage Loan Schedule, included as Exhibit D to the Pooling and Servicing Agreement, has been intentionally omitted from this filing. Copies may be obtained from Washington Mutual Mortgage Securities Corp. or Citibank, N.A. by contacting,

in the case of Washington Mutual Mortgage Securities Corp.,

Laura Kelsey Master Servicing Department Washington Mutual Mortgage Securities Corp. 75 N. Fairway Drive,VHF2A01 Vernon Hills, IL 60061 Telephone: (847) 393-5198 Facsimile: (847) 549-2997

in the case of Citibank, N.A.

Karen Schluter Corporate Trust Office Citibank, N.A. 111 Wall Street, 14th Floor, New York, NY 10005 Telephone: (212) 657-7781 Facsimile: (212) 657-4009

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

		WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
Date: August 7, 2003		By:		/s/ David H. Zielke David H. Zielke First Vice President and Counsel

Filing Compare · WAMU MORTGAGE PASS-THROUGH CERTIFICATES SERIES 2003-S7