Wamu Mortgage Pass Through Certs Ser 2003-S11 Sample Contracts

Wamu Mortgage Pass Through Certs Ser 2003-S11 – WASHINGTON MUTUAL MORTGAGE SECURITIES CORP. (December 29th, 2004)

The Group B Certificates provide, to the limited extent described in the Prospectus Supplement, credit support, as well as special hazard, bankruptcy, and fraud coverage to certain Certificates. The "Prospectus Supplement" is that certain Prospectus Supplement, dated October 21,2003 to that certain Prospectus Supplement, dated September 19,2003, to which certain certificates were offered. The special hazard, bankruptcy, and Fraud coverage (collectively, "Credit Enhancements") provided by the B certificates provide coverage to the Loans, subject to the conditions and limitations to payment specified thereunder.

Wamu Mortgage Pass Through Certs Ser 2003-S11 – WASHINGTON MUTUAL MORTGAGE SECURITIES CORP. (November 30th, 2004)

The Group B Certificates provide, to the limited extent described in the Prospectus Supplement, credit support, as well as special hazard, bankruptcy, and fraud coverage to certain Certificates. The "Prospectus Supplement" is that certain Prospectus Supplement, dated October 21,2003 to that certain Prospectus Supplement, dated September 19,2003, to which certain certificates were offered. The special hazard, bankruptcy, and Fraud coverage (collectively, "Credit Enhancements") provided by the B certificates provide coverage to the Loans, subject to the conditions and limitations to payment specified thereunder.

Wamu Mortgage Pass Through Certs Ser 2003-S11 – WASHINGTON MUTUAL MORTGAGE SECURITIES CORP. (October 27th, 2004)

The Group B Certificates provide, to the limited extent described in the Prospectus Supplement, credit support, as well as special hazard, bankruptcy, and fraud coverage to certain Certificates. The "Prospectus Supplement" is that certain Prospectus Supplement, dated October 21,2003 to that certain Prospectus Supplement, dated September 19,2003, to which certain certificates were offered. The special hazard, bankruptcy, and Fraud coverage (collectively, "Credit Enhancements") provided by the B certificates provide coverage to the Loans, subject to the conditions and limitations to payment specified thereunder.

Wamu Mortgage Pass Through Certs Ser 2003-S11 – WASHINGTON MUTUAL MORTGAGE SECURITIES CORP. (September 29th, 2004)

The Group B Certificates provide, to the limited extent described in the Prospectus Supplement, credit support, as well as special hazard, bankruptcy, and fraud coverage to certain Certificates. The "Prospectus Supplement" is that certain Prospectus Supplement, dated October 21,2003 to that certain Prospectus Supplement, dated September 19,2003, to which certain certificates were offered. The special hazard, bankruptcy, and Fraud coverage (collectively, "Credit Enhancements") provided by the B certificates provide coverage to the Loans, subject to the conditions and limitations to payment specified thereunder.

Wamu Mortgage Pass Through Certs Ser 2003-S11 – WASHINGTON MUTUAL MORTGAGE SECURITIES CORP. (August 27th, 2004)

The Group B Certificates provide, to the limited extent described in the Prospectus Supplement, credit support, as well as special hazard, bankruptcy, and fraud coverage to certain Certificates. The "Prospectus Supplement" is that certain Prospectus Supplement, dated October 21,2003 to that certain Prospectus Supplement, dated September 19,2003, to which certain certificates were offered. The special hazard, bankruptcy, and Fraud coverage (collectively, "Credit Enhancements") provided by the B certificates provide coverage to the Loans, subject to the conditions and limitations to payment specified thereunder.

Wamu Mortgage Pass Through Certs Ser 2003-S11 – WASHINGTON MUTUAL MORTGAGE SECURITIES CORP. (July 30th, 2004)

The Group B Certificates provide, to the limited extent described in the Prospectus Supplement, credit support, as well as special hazard, bankruptcy, and fraud coverage to certain Certificates. The "Prospectus Supplement" is that certain Prospectus Supplement, dated October 21,2003 to that certain Prospectus Supplement, dated September 19,2003, to which certain certificates were offered. The special hazard, bankruptcy, and Fraud coverage (collectively, "Credit Enhancements") provided by the B certificates provide coverage to the Loans, subject to the conditions and limitations to payment specified thereunder.

Wamu Mortgage Pass Through Certs Ser 2003-S11 – WASHINGTON MUTUAL MORTGAGE SECURITIES CORP. (July 2nd, 2004)

The Group B Certificates provide, to the limited extent described in the Prospectus Supplement, credit support, as well as special hazard, bankruptcy, and fraud coverage to certain Certificates. The "Prospectus Supplement" is that certain Prospectus Supplement, dated October 21,2003 to that certain Prospectus Supplement, dated September 19,2003, to which certain certificates were offered. The special hazard, bankruptcy, and Fraud coverage (collectively, "Credit Enhancements") provided by the B certificates provide coverage to the Loans, subject to the conditions and limitations to payment specified thereunder.

Wamu Mortgage Pass Through Certs Ser 2003-S11 – WASHINGTON MUTUAL MORTGAGE SECURITIES CORP. (June 4th, 2004)

The Group B Certificates provide, to the limited extent described in the Prospectus Supplement, credit support, as well as special hazard, bankruptcy, and fraud coverage to certain Certificates. The "Prospectus Supplement" is that certain Prospectus Supplement, dated October 21,2003 to that certain Prospectus Supplement, dated September 19,2003, to which certain certificates were offered. The special hazard, bankruptcy, and Fraud coverage (collectively, "Credit Enhancements") provided by the B certificates provide coverage to the Loans, subject to the conditions and limitations to payment specified thereunder.

Wamu Mortgage Pass Through Certs Ser 2003-S11 – WASHINGTON MUTUAL MORTGAGE SECURITIES CORP. (May 4th, 2004)

The Group B Certificates provide, to the limited extent described in the Prospectus Supplement, credit support, as well as special hazard, bankruptcy, and fraud coverage to certain Certificates. The "Prospectus Supplement" is that certain Prospectus Supplement, dated October 21,2003 to that certain Prospectus Supplement, dated September 19,2003, to which certain certificates were offered. The special hazard, bankruptcy, and Fraud coverage (collectively, "Credit Enhancements") provided by the B certificates provide coverage to the Loans, subject to the conditions and limitations to payment specified thereunder.

Wamu Mortgage Pass Through Certs Ser 2003-S11 – WASHINGTON MUTUAL MORTGAGE SECURITIES CORP. (April 5th, 2004)

The Group B Certificates provide, to the limited extent described in the Prospectus Supplement, credit support, as well as special hazard, bankruptcy, and fraud coverage to certain Certificates. The "Prospectus Supplement" is that certain Prospectus Supplement, dated October 21,2003 to that certain Prospectus Supplement, dated September 19,2003, to which certain certificates were offered. The special hazard, bankruptcy, and Fraud coverage (collectively, "Credit Enhancements") provided by the B certificates provide coverage to the Loans, subject to the conditions and limitations to payment specified thereunder.

Wamu Mortgage Pass Through Certs Ser 2003-S11 – WASHINGTON MUTUAL MORTGAGE SECURITIES CORP. (March 3rd, 2004)

The Group B Certificates provide, to the limited extent described in the Prospectus Supplement, credit support, as well as special hazard, bankruptcy, and fraud coverage to certain Certificates. The "Prospectus Supplement" is that certain Prospectus Supplement, dated October 21,2003 to that certain Prospectus Supplement, dated September 19,2003, to which certain certificates were offered. The special hazard, bankruptcy, and Fraud coverage (collectively, "Credit Enhancements") provided by the B certificates provide coverage to the Loans, subject to the conditions and limitations to payment specified thereunder.

Wamu Mortgage Pass Through Certs Ser 2003-S11 – WASHINGTON MUTUAL MORTGAGE SECURITIES CORP. (February 4th, 2004)

The Group B Certificates provide, to the limited extent described in the Prospectus Supplement, credit support, as well as special hazard, bankruptcy, and fraud coverage to certain Certificates. The "Prospectus Supplement" is that certain Prospectus Supplement, dated October 21,2003 to that certain Prospectus Supplement, dated September 19,2003, to which certain certificates were offered. The special hazard, bankruptcy, and Fraud coverage (collectively, "Credit Enhancements") provided by the B certificates provide coverage to the Loans, subject to the conditions and limitations to payment specified thereunder.

Wamu Mortgage Pass Through Certs Ser 2003-S11 – WASHINGTON MUTUAL MORTGAGE SECURITIES CORP. (January 7th, 2004)

The Group B Certificates provide, to the limited extent described in the Prospectus Supplement, credit support, as well as special hazard, bankruptcy, and fraud coverage to certain Certificates. The "Prospectus Supplement" is that certain Prospectus Supplement, dated October 21,2003 to that certain Prospectus Supplement, dated September 19,2003, to which certain certificates were offered. The special hazard, bankruptcy, and Fraud coverage (collectively, "Credit Enhancements") provided by the B certificates provide coverage to the Loans, subject to the conditions and limitations to payment specified thereunder.

Wamu Mortgage Pass Through Certs Ser 2003-S11 – WASHINGTON MUTUAL MORTGAGE SECURITIES CORP. (December 4th, 2003)

The Group B Certificates provide, to the limited extent described in the Prospectus Supplement, credit support, as well as special hazard, bankruptcy, and fraud coverage to certain Certificates. The "Prospectus Supplement" is that certain Prospectus Supplement, dated October 21,2003 to that certain Prospectus Supplement, dated September 19,2003, to which certain certificates were offered. The special hazard, bankruptcy, and Fraud coverage (collectively, "Credit Enhancements") provided by the B certificates provide coverage to the Loans, subject to the conditions and limitations to payment specified thereunder.

Wamu Mortgage Pass Through Certs Ser 2003-S11 – WASHINGTON MUTUAL MORTGAGE SECURITIES CORP., (November 10th, 2003)

Exhibit 7.1 EXECUTION VERSION WASHINGTON MUTUAL MORTGAGE SECURITIES CORP., as Depositor and Master Servicer and CITIBANK, N.A., as Trustee and CHRISTIANA BANK & TRUST COMPANY, as Delaware Trustee POOLING AND SERVICING AGREEMENT $1,419,849,766.31 Washington Mutual Mortgage Securities Corp. WaMu Mortgage Pass-Through Certificates Series 2003-S11 Cut-Off Date: October 1, 2003 TABLE OF CONTENTS