WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
Series: WAMMS.03MS3
Distribution Date: 08/25/2003

Class	Cusip	Orig Prin Bal	Begin Prin Bal	Int Rate Accrued	Int Rate Paid	Int Dist	Prin Dist	Int Shortfall	Prin Loss	Deferred Interest	Int Reimbursed	Unscheduled Int	Prin Reimbursed	Total Dist	Ending Class Bal
IA1	939336RW5	$300,000,000.00	$177,813,840.30	5.7500000000%	5.7500000000%	$852,024.65	$40,803,318.30	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$41,655,342.95	$137,010,522.00
IA2	939336RX3	$25,000,000.00	$25,000,000.00	5.7500000000%	5.7500000000%	$119,791.67	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$119,791.67	$25,000,000.00
IA3	939336RY1	$1,000,000.00	$1,000,000.00	5.5000000000%	5.5000000000%	$4,583.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$4,583.33	$1,000,000.00
IA4	939336RZ8	$46,000,000.00	$46,000,000.00	5.7500000000%	5.7500000000%	$220,416.67	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$220,416.67	$46,000,000.00
IA5	939336SA2	$6,992,000.00	$6,992,000.00	5.7500000000%	5.7500000000%	$33,503.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$33,503.33	$6,992,000.00
IA6	939336SB0	$1,000,000.00	$1,000,000.00	5.5000000000%	5.5000000000%	$4,583.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$4,583.33	$1,000,000.00
IA7	939336SC8	$1,000,000.00	$1,000,000.00	5.5000000000%	5.5000000000%	$4,583.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$4,583.33	$1,000,000.00
IA8	939336SD6	$1,000,000.00	$1,000,000.00	5.5000000000%	5.5000000000%	$4,583.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$4,583.33	$1,000,000.00
IA9	939336SE4	$1,000,000.00	$1,000,000.00	5.5000000000%	5.5000000000%	$4,583.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$4,583.33	$1,000,000.00
IA10	939336SF1	$1,000,000.00	$1,000,000.00	5.5000000000%	5.5000000000%	$4,583.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$4,583.33	$1,000,000.00
IA11	939336SG9	$1,000,000.00	$1,000,000.00	5.5000000000%	5.5000000000%	$4,583.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$4,583.33	$1,000,000.00
IA12	939336SH7	$1,000,000.00	$1,000,000.00	5.5000000000%	5.5000000000%	$4,583.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$4,583.33	$1,000,000.00
IA13	939336SJ3	$1,000,000.00	$1,000,000.00	5.5000000000%	5.5000000000%	$4,583.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$4,583.33	$1,000,000.00
IA14	939336SK0	$1,000,000.00	$1,000,000.00	5.5000000000%	5.5000000000%	$4,583.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$4,583.33	$1,000,000.00
IA15	939336SL8	$3,000,000.00	$3,000,000.00	5.7500000000%	5.7500000000%	$14,375.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$14,375.00	$3,000,000.00
IA16	939336SM6	$3,000,000.00	$3,000,000.00	5.7500000000%	5.7500000000%	$14,375.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$14,375.00	$3,000,000.00
IA17	939336SN4	$3,000,000.00	$3,000,000.00	5.7500000000%	5.7500000000%	$14,375.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$14,375.00	$3,000,000.00
IA18	939336SP9	$3,000,000.00	$3,000,000.00	5.7500000000%	5.7500000000%	$14,375.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$14,375.00	$3,000,000.00
IA19	939336SQ7	$1,500,000.00	$1,500,000.00	6.0000000000%	6.0000000000%	$7,500.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$7,500.00	$1,500,000.00
IA20	939336SR5	$1,500,000.00	$1,500,000.00	5.5000000000%	5.5000000000%	$6,875.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$6,875.00	$1,500,000.00
IA21	939336SS3	$1,086,956.52	$1,086,956.52	5.7500000000%	5.7500000000%	$5,208.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$5,208.33	$1,086,956.52
IA22	939336VW0	$50,627,000.00	$32,494,537.57	5.7500000000%	5.7500000000%	$155,702.99	$6,055,224.57	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$6,210,927.56	$26,439,313.00
IA23	939336VX8	$25,059,375.00	$16,300,031.71	4.5000000000%	4.5000000000%	$61,125.12	$2,925,128.95	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$2,986,254.07	$13,374,902.76
IA24	939336VY6	$24,850,000.00	$24,850,000.00	5.7500000000%	5.7500000000%	$119,072.92	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$119,072.92	$24,850,000.00
IA25	939336VZ3	$11,390,625.00	$7,409,105.33	1.7250000000%	1.7250000000%	$10,650.59	$1,329,604.07	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,340,254.66	$6,079,501.26
IA26	939336WA7	$11,390,625.00	$7,409,105.33	6.7750000000%	6.7750000000%	$41,830.57	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$41,830.57	$6,079,501.26
IA27	939336WB5	$400,000.00	$400,000.00	5.5000000000%	5.5000000000%	$1,833.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,833.33	$400,000.00
IA28	939336WC3	$400,000.00	$400,000.00	5.5000000000%	5.5000000000%	$1,833.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,833.33	$400,000.00
IA29	939336WD1	$400,000.00	$400,000.00	5.5000000000%	5.5000000000%	$1,833.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,833.33	$400,000.00
IA30	939336WE9	$400,000.00	$400,000.00	5.5000000000%	5.5000000000%	$1,833.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,833.33	$400,000.00
IA31	939336WF6	$400,000.00	$400,000.00	5.5000000000%	5.5000000000%	$1,833.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,833.33	$400,000.00

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
Series: WAMMS.03MS3
Distribution Date: 08/25/2003

Class	Cusip	Orig Prin Bal	Begin Prin Bal	Int Rate Accrued	Int Rate Paid	Int Dist	Prin Dist	Int Shortfall	Prin Loss	Deferred Interest	Int Reimbursed	Unscheduled Int	Prin Reimbursed	Total Dist	Ending Class Bal
IA32	939336WG4	$400,000.00	$400,000.00	5.5000000000%	5.5000000000%	$1,833.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,833.33	$400,000.00
IA33	939336WH2	$400,000.00	$400,000.00	5.5000000000%	5.5000000000%	$1,833.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,833.33	$400,000.00
IA34	939336WJ8	$400,000.00	$400,000.00	5.5000000000%	5.5000000000%	$1,833.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,833.33	$400,000.00
IA35	939336WK5	$400,000.00	$400,000.00	5.5000000000%	5.5000000000%	$1,833.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,833.33	$400,000.00
IA36	939336WL3	$400,000.00	$400,000.00	5.5000000000%	5.5000000000%	$1,833.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,833.33	$400,000.00
IA37	939336WM1	$400,000.00	$400,000.00	5.5000000000%	5.5000000000%	$1,833.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,833.33	$400,000.00
IA38	939336WN9	$400,000.00	$400,000.00	5.5000000000%	5.5000000000%	$1,833.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,833.33	$400,000.00
IA39	939336WP4	$400,000.00	$400,000.00	5.5000000000%	5.5000000000%	$1,833.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,833.33	$400,000.00
IA40	939336WQ2	$400,000.00	$400,000.00	5.5000000000%	5.5000000000%	$1,833.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,833.33	$400,000.00
IA41	939336WR0	$400,000.00	$400,000.00	5.5000000000%	5.5000000000%	$1,833.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,833.33	$400,000.00
IA42	939336WS8	$400,000.00	$400,000.00	5.5000000000%	5.5000000000%	$1,833.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,833.33	$400,000.00
IA43	939336WT6	$400,000.00	$400,000.00	5.5000000000%	5.5000000000%	$1,833.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,833.33	$400,000.00
IA44	939336WU3	$400,000.00	$400,000.00	5.5000000000%	5.5000000000%	$1,833.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,833.33	$400,000.00
IA45	939336WV1	$400,000.00	$400,000.00	5.5000000000%	5.5000000000%	$1,833.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,833.33	$400,000.00
IA46	939336WW9	$400,000.00	$400,000.00	5.5000000000%	5.5000000000%	$1,833.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,833.33	$400,000.00
IA47	939336WX7	$400,000.00	$400,000.00	5.5000000000%	5.5000000000%	$1,833.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,833.33	$400,000.00
IA48	939336WY5	$400,000.00	$400,000.00	5.5000000000%	5.5000000000%	$1,833.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,833.33	$400,000.00
IA49	939336WZ2	$400,000.00	$400,000.00	5.5000000000%	5.5000000000%	$1,833.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,833.33	$400,000.00
IA50	939336XA6	$400,000.00	$400,000.00	5.5000000000%	5.5000000000%	$1,833.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,833.33	$400,000.00
IA51	939336XB4	$400,000.00	$400,000.00	5.5000000000%	5.5000000000%	$1,833.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,833.33	$400,000.00
IA52	939336XC2	$400,000.00	$400,000.00	5.5000000000%	5.5000000000%	$1,833.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,833.33	$400,000.00
IA53	939336XD0	$400,000.00	$400,000.00	5.5000000000%	5.5000000000%	$1,833.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,833.33	$400,000.00
IA54	939336XE8	$400,000.00	$400,000.00	5.5000000000%	5.5000000000%	$1,833.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,833.33	$400,000.00
IA55	939336XF5	$400,000.00	$400,000.00	5.5000000000%	5.5000000000%	$1,833.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,833.33	$400,000.00
IA56	939336XG3	$400,000.00	$400,000.00	5.5000000000%	5.5000000000%	$1,833.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,833.33	$400,000.00
IA57	939336XH1	$400,000.00	$400,000.00	5.5000000000%	5.5000000000%	$1,833.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,833.33	$400,000.00
IA58	939336XJ7	$400,000.00	$400,000.00	5.5000000000%	5.5000000000%	$1,833.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,833.33	$400,000.00
IA59	939336XK4	$400,000.00	$400,000.00	5.5000000000%	5.5000000000%	$1,833.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,833.33	$400,000.00
IA60	939336XL2	$400,000.00	$400,000.00	5.5000000000%	5.5000000000%	$1,833.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,833.33	$400,000.00
IA61	939336XM0	$400,000.00	$400,000.00	5.5000000000%	5.5000000000%	$1,833.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,833.33	$400,000.00
IA62	939336XN8	$400,000.00	$400,000.00	5.5000000000%	5.5000000000%	$1,833.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,833.33	$400,000.00

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
Series: WAMMS.03MS3
Distribution Date: 08/25/2003

Class	Cusip	Orig Prin Bal	Begin Prin Bal	Int Rate Accrued	Int Rate Paid	Int Dist	Prin Dist	Int Shortfall	Prin Loss	Deferred Interest	Int Reimbursed	Unscheduled Int	Prin Reimbursed	Total Dist	Ending Class Bal
IA63	939336XP3	$600,000.00	$600,000.00	5.5000000000%	5.5000000000%	$2,750.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$2,750.00	$600,000.00
IIA1	939336XQ1	$125,395,000.00	$90,483,877.34	5.2500000000%	5.2500000000%	$395,866.96	$10,687,947.40	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$11,083,814.36	$79,795,929.94
IIA2	939336XR9	$52,370,500.00	$37,790,070.55	4.5000000000%	4.5000000000%	$141,712.76	$4,463,759.71	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$4,605,472.48	$33,326,310.84
IIA3	939336XS7	$327,000.00	$235,960.19	4.5000000000%	4.5000000000%	$884.85	$27,871.60	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$28,756.45	$208,088.59
IIA4	939336XT5	$10,000,000.00	$7,215,907.91	4.5000000000%	4.5000000000%	$27,059.65	$852,342.39	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$879,402.04	$6,363,565.52
IIA5	939336XU2	$3,500,000.00	$2,525,567.77	5.0000000000%	5.0000000000%	$10,523.20	$298,319.84	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$308,843.04	$2,227,247.93
IIA6	939336XV0	$10,000,000.00	$7,215,907.91	5.0000000000%	5.0000000000%	$30,066.28	$852,342.39	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$882,408.67	$6,363,565.52
IX	939336SU8	$6,779,035.00	$4,490,565.39	5.7500000000%	5.7500000000%	$21,517.29	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$21,517.29	$3,965,302.03
IIX	939336SV6	$12,486,599.00	$8,238,772.49	5.0000000000%	5.0000000000%	$34,328.22	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$34,328.22	$7,219,999.36
IP	939336SW4	$1,101,174.80	$1,052,023.95	0.0000000000%	0.0000000000%	$0.00	$50,335.72	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$50,335.72	$1,001,688.23
IIP	939336SX2	$96,394.50	$94,515.23	0.0000000000%	0.0000000000%	$0.00	$373.25	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$373.25	$94,141.98
CB1	939336SY0	$9,418,327.00	$9,337,921.80	5.5455848907%	5.5455848907%	$43,153.53	$16,474.93	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$59,628.46	$9,321,446.87
CB2	939336SZ7	$4,520,574.00	$4,481,981.42	5.5455848907%	5.5455848907%	$20,712.67	$7,907.58	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$28,620.25	$4,474,073.84
CB3	939336TA1	$3,013,716.00	$2,987,987.61	5.5455848907%	5.5455848907%	$13,808.45	$5,271.72	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$19,080.17	$2,982,715.89
CB4	939336TC7	$1,130,143.00	$1,120,494.86	5.5455848907%	5.5455848907%	$5,178.17	$1,976.89	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$7,155.06	$1,118,517.97
CB5	939336TD5	$1,130,143.00	$1,120,494.86	5.5455848907%	5.5455848907%	$5,178.17	$1,976.89	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$7,155.06	$1,118,517.97
CB6	939336TE3	$1,506,857.67	$1,493,993.49	5.5455848907%	5.5455848907%	$6,904.22	$2,635.86	$0.00	$0.02	$0.00	$0.00	$0.00	$0.00	$9,540.08	$1,491,357.62
R	939336TB9	$100.00	$0.00	0.0000000000%	0.0000000000%	$0.06	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.06	$0.00
R_SYN	XXXXXXXXX	$0.00	$0.00	0.0000000000%	0.0000000000%	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00
Total		$753,428,929.97	$544,016,219.80			$2,562,679.67	$68,382,812.04	$0.00	$0.02	$0.00	$0.00	$0.00	$0.00	$70,945,491.71	$475,633,407.74

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
Series: WAMMS.03MS3
Distribution Date: 08/25/2003

Class	Orig Face	Beg Bal	Prin Loss	Deferred Interest	Total Prin	End Cert Pct	End Cert Bal
IA1	$300,000,000.00	$177,813,840.30	$0.00	$0.00	$40,803,318.30	0.4567017400	$137,010,522.00
IA2	$25,000,000.00	$25,000,000.00	$0.00	$0.00	$0.00	1.0000000000	$25,000,000.00
IA3	$1,000,000.00	$1,000,000.00	$0.00	$0.00	$0.00	1.0000000000	$1,000,000.00
IA4	$46,000,000.00	$46,000,000.00	$0.00	$0.00	$0.00	1.0000000000	$46,000,000.00
IA5	$6,992,000.00	$6,992,000.00	$0.00	$0.00	$0.00	1.0000000000	$6,992,000.00
IA6	$1,000,000.00	$1,000,000.00	$0.00	$0.00	$0.00	1.0000000000	$1,000,000.00
IA7	$1,000,000.00	$1,000,000.00	$0.00	$0.00	$0.00	1.0000000000	$1,000,000.00
IA8	$1,000,000.00	$1,000,000.00	$0.00	$0.00	$0.00	1.0000000000	$1,000,000.00
IA9	$1,000,000.00	$1,000,000.00	$0.00	$0.00	$0.00	1.0000000000	$1,000,000.00
IA10	$1,000,000.00	$1,000,000.00	$0.00	$0.00	$0.00	1.0000000000	$1,000,000.00
IA11	$1,000,000.00	$1,000,000.00	$0.00	$0.00	$0.00	1.0000000000	$1,000,000.00
IA12	$1,000,000.00	$1,000,000.00	$0.00	$0.00	$0.00	1.0000000000	$1,000,000.00
IA13	$1,000,000.00	$1,000,000.00	$0.00	$0.00	$0.00	1.0000000000	$1,000,000.00
IA14	$1,000,000.00	$1,000,000.00	$0.00	$0.00	$0.00	1.0000000000	$1,000,000.00
IA15	$3,000,000.00	$3,000,000.00	$0.00	$0.00	$0.00	1.0000000000	$3,000,000.00
IA16	$3,000,000.00	$3,000,000.00	$0.00	$0.00	$0.00	1.0000000000	$3,000,000.00
IA17	$3,000,000.00	$3,000,000.00	$0.00	$0.00	$0.00	1.0000000000	$3,000,000.00
IA18	$3,000,000.00	$3,000,000.00	$0.00	$0.00	$0.00	1.0000000000	$3,000,000.00
IA19	$1,500,000.00	$1,500,000.00	$0.00	$0.00	$0.00	1.0000000000	$1,500,000.00
IA20	$1,500,000.00	$1,500,000.00	$0.00	$0.00	$0.00	1.0000000000	$1,500,000.00
IA21	$1,086,956.52	$1,086,956.52	$0.00	$0.00	$0.00	1.0000000000	$1,086,956.52
IA22	$50,627,000.00	$32,494,537.57	$0.00	$0.00	$6,055,224.57	0.5222374030	$26,439,313.00
IA23	$25,059,375.00	$16,300,031.71	$0.00	$0.00	$2,925,128.95	0.5337285052	$13,374,902.76
IA24	$24,850,000.00	$24,850,000.00	$0.00	$0.00	$0.00	1.0000000000	$24,850,000.00
IA25	$11,390,625.00	$7,409,105.33	$0.00	$0.00	$1,329,604.07	0.5337285057	$6,079,501.26
IA26	$11,390,625.00	$7,409,105.33	$0.00	$0.00	$0.00	0.5337285057	$6,079,501.26
IA27	$400,000.00	$400,000.00	$0.00	$0.00	$0.00	1.0000000000	$400,000.00
IA28	$400,000.00	$400,000.00	$0.00	$0.00	$0.00	1.0000000000	$400,000.00
IA29	$400,000.00	$400,000.00	$0.00	$0.00	$0.00	1.0000000000	$400,000.00
IA30	$400,000.00	$400,000.00	$0.00	$0.00	$0.00	1.0000000000	$400,000.00
IA31	$400,000.00	$400,000.00	$0.00	$0.00	$0.00	1.0000000000	$400,000.00

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
Series: WAMMS.03MS3
Distribution Date: 08/25/2003

Class	Orig Face	Beg Bal	Prin Loss	Deferred Interest	Total Prin	End Cert Pct	End Cert Bal
IA32	$400,000.00	$400,000.00	$0.00	$0.00	$0.00	1.0000000000	$400,000.00
IA33	$400,000.00	$400,000.00	$0.00	$0.00	$0.00	1.0000000000	$400,000.00
IA34	$400,000.00	$400,000.00	$0.00	$0.00	$0.00	1.0000000000	$400,000.00
IA35	$400,000.00	$400,000.00	$0.00	$0.00	$0.00	1.0000000000	$400,000.00
IA36	$400,000.00	$400,000.00	$0.00	$0.00	$0.00	1.0000000000	$400,000.00
IA37	$400,000.00	$400,000.00	$0.00	$0.00	$0.00	1.0000000000	$400,000.00
IA38	$400,000.00	$400,000.00	$0.00	$0.00	$0.00	1.0000000000	$400,000.00
IA39	$400,000.00	$400,000.00	$0.00	$0.00	$0.00	1.0000000000	$400,000.00
IA40	$400,000.00	$400,000.00	$0.00	$0.00	$0.00	1.0000000000	$400,000.00
IA41	$400,000.00	$400,000.00	$0.00	$0.00	$0.00	1.0000000000	$400,000.00
IA42	$400,000.00	$400,000.00	$0.00	$0.00	$0.00	1.0000000000	$400,000.00
IA43	$400,000.00	$400,000.00	$0.00	$0.00	$0.00	1.0000000000	$400,000.00
IA44	$400,000.00	$400,000.00	$0.00	$0.00	$0.00	1.0000000000	$400,000.00
IA45	$400,000.00	$400,000.00	$0.00	$0.00	$0.00	1.0000000000	$400,000.00
IA46	$400,000.00	$400,000.00	$0.00	$0.00	$0.00	1.0000000000	$400,000.00
IA47	$400,000.00	$400,000.00	$0.00	$0.00	$0.00	1.0000000000	$400,000.00
IA48	$400,000.00	$400,000.00	$0.00	$0.00	$0.00	1.0000000000	$400,000.00
IA49	$400,000.00	$400,000.00	$0.00	$0.00	$0.00	1.0000000000	$400,000.00
IA50	$400,000.00	$400,000.00	$0.00	$0.00	$0.00	1.0000000000	$400,000.00
IA51	$400,000.00	$400,000.00	$0.00	$0.00	$0.00	1.0000000000	$400,000.00
IA52	$400,000.00	$400,000.00	$0.00	$0.00	$0.00	1.0000000000	$400,000.00
IA53	$400,000.00	$400,000.00	$0.00	$0.00	$0.00	1.0000000000	$400,000.00
IA54	$400,000.00	$400,000.00	$0.00	$0.00	$0.00	1.0000000000	$400,000.00
IA55	$400,000.00	$400,000.00	$0.00	$0.00	$0.00	1.0000000000	$400,000.00
IA56	$400,000.00	$400,000.00	$0.00	$0.00	$0.00	1.0000000000	$400,000.00
IA57	$400,000.00	$400,000.00	$0.00	$0.00	$0.00	1.0000000000	$400,000.00
IA58	$400,000.00	$400,000.00	$0.00	$0.00	$0.00	1.0000000000	$400,000.00
IA59	$400,000.00	$400,000.00	$0.00	$0.00	$0.00	1.0000000000	$400,000.00
IA60	$400,000.00	$400,000.00	$0.00	$0.00	$0.00	1.0000000000	$400,000.00
IA61	$400,000.00	$400,000.00	$0.00	$0.00	$0.00	1.0000000000	$400,000.00
IA62	$400,000.00	$400,000.00	$0.00	$0.00	$0.00	1.0000000000	$400,000.00

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
Series: WAMMS.03MS3
Distribution Date: 08/25/2003

Class	Orig Face	Beg Bal	Prin Loss	Deferred Interest	Total Prin	End Cert Pct	End Cert Bal
IA63	$600,000.00	$600,000.00	$0.00	$0.00	$0.00	1.0000000000	$600,000.00
IIA1	$125,395,000.00	$90,483,877.34	$0.00	$0.00	$10,687,947.40	0.6363565528	$79,795,929.94
IIA2	$52,370,500.00	$37,790,070.55	$0.00	$0.00	$4,463,759.71	0.6363565526	$33,326,310.84
IIA3	$327,000.00	$235,960.19	$0.00	$0.00	$27,871.60	0.6363565443	$208,088.59
IIA4	$10,000,000.00	$7,215,907.91	$0.00	$0.00	$852,342.39	0.6363565520	$6,363,565.52
IIA5	$3,500,000.00	$2,525,567.77	$0.00	$0.00	$298,319.84	0.6363565514	$2,227,247.93
IIA6	$10,000,000.00	$7,215,907.91	$0.00	$0.00	$852,342.39	0.6363565520	$6,363,565.52
IX	$6,779,035.00	$4,490,565.39	$0.00	$0.00	$0.00	0.5849360610	$3,965,302.03
IIX	$12,486,599.00	$8,238,772.49	$0.00	$0.00	$0.00	0.5782198467	$7,219,999.36
IP	$1,101,174.80	$1,052,023.95	$0.00	$0.00	$50,335.72	0.9096541530	$1,001,688.23
IIP	$96,394.50	$94,515.23	$0.00	$0.00	$373.25	0.9766322767	$94,141.98
CB1	$9,418,327.00	$9,337,921.80	$0.00	$0.00	$16,474.93	0.9897136583	$9,321,446.87
CB2	$4,520,574.00	$4,481,981.42	$0.00	$0.00	$7,907.58	0.9897136603	$4,474,073.84
CB3	$3,013,716.00	$2,987,987.61	$0.00	$0.00	$5,271.72	0.9897136592	$2,982,715.89
CB4	$1,130,143.00	$1,120,494.86	$0.00	$0.00	$1,976.89	0.9897136646	$1,118,517.97
CB5	$1,130,143.00	$1,120,494.86	$0.00	$0.00	$1,976.89	0.9897136646	$1,118,517.97
CB6	$1,506,857.67	$1,493,993.49	$0.02	$0.00	$2,635.86	0.9897136602	$1,491,357.62
R	$100.00	$0.00	$0.00	$0.00	$0.00	0.0000000000	$0.00
R_SYN	$0.00	$0.00	$0.00	$0.00	$0.00	0.0000000000	$0.00
Total	$753,428,929.97	$544,016,219.80	$0.02	$0.00	$68,382,812.04	0.6312916704	$475,633,407.74

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
Series: WAMMS.03MS3
Distribution Date: 08/25/2003
PER $1000 DENOMINATION
Class	Orig Face	Beg Bal	Prin Loss	Deferred Interest	Total Prin	End Cert Pct	End Cert Bal
IA1	$300,000,000.00	592.71280100	0.00000000	0.00000000	136.01106100	0.4567017400	456.70174000
IA2	$25,000,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA3	$1,000,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA4	$46,000,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA5	$6,992,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA6	$1,000,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA7	$1,000,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA8	$1,000,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA9	$1,000,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA10	$1,000,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA11	$1,000,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA12	$1,000,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA13	$1,000,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA14	$1,000,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA15	$3,000,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA16	$3,000,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA17	$3,000,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA18	$3,000,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA19	$1,500,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA20	$1,500,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA21	$1,086,956.52	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA22	$50,627,000.00	641.84205207	0.00000000	0.00000000	119.60464910	0.5222374030	522.23740297
IA23	$25,059,375.00	650.45643437	0.00000000	0.00000000	116.72792917	0.5337285052	533.72850520
IA24	$24,850,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA25	$11,390,625.00	650.45643501	0.00000000	0.00000000	116.72792933	0.5337285057	533.72850568
IA26	$11,390,625.00	650.45643501	0.00000000	0.00000000	0.00000000	0.5337285057	533.72850568
IA27	$400,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA28	$400,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA29	$400,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA30	$400,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA31	$400,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
Series: WAMMS.03MS3
Distribution Date: 08/25/2003
PER $1000 DENOMINATION
Class	Orig Face	Beg Bal	Prin Loss	Deferred Interest	Total Prin	End Cert Pct	End Cert Bal
IA32	$400,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA33	$400,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA34	$400,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA35	$400,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA36	$400,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA37	$400,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA38	$400,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA39	$400,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA40	$400,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA41	$400,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA42	$400,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA43	$400,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA44	$400,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA45	$400,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA46	$400,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA47	$400,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA48	$400,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA49	$400,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA50	$400,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA51	$400,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA52	$400,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA53	$400,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA54	$400,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA55	$400,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA56	$400,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA57	$400,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA58	$400,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA59	$400,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA60	$400,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA61	$400,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IA62	$400,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
Series: WAMMS.03MS3
Distribution Date: 08/25/2003
PER $1000 DENOMINATION
Class	Orig Face	Beg Bal	Prin Loss	Deferred Interest	Total Prin	End Cert Pct	End Cert Bal
IA63	$600,000.00	1,000.00000000	0.00000000	0.00000000	0.00000000	1.0000000000	1,000.00000000
IIA1	$125,395,000.00	721.59079182	0.00000000	0.00000000	85.23423900	0.6363565528	636.35655281
IIA2	$52,370,500.00	721.59079157	0.00000000	0.00000000	85.23423893	0.6363565526	636.35655264
IIA3	$327,000.00	721.59079511	0.00000000	0.00000000	85.23425076	0.6363565443	636.35654434
IIA4	$10,000,000.00	721.59079100	0.00000000	0.00000000	85.23423900	0.6363565520	636.35655200
IIA5	$3,500,000.00	721.59079143	0.00000000	0.00000000	85.23424000	0.6363565514	636.35655143
IIA6	$10,000,000.00	721.59079100	0.00000000	0.00000000	85.23423900	0.6363565520	636.35655200
IX	$6,779,035.00	662.41956119	0.00000000	0.00000000	0.00000000	0.5849360610	584.93606096
IIX	$12,486,599.00	659.80916741	0.00000000	0.00000000	0.00000000	0.5782198467	578.21984673
IP	$1,101,174.80	955.36507919	0.00000000	0.00000000	45.71092619	0.9096541530	909.65415300
IIP	$96,394.50	980.50438562	0.00000000	0.00000000	3.87210889	0.9766322767	976.63227674
CB1	$9,418,327.00	991.46289994	0.00000000	0.00000000	1.74924166	0.9897136583	989.71365827
CB2	$4,520,574.00	991.46290272	0.00000000	0.00000000	1.74924246	0.9897136603	989.71366026
CB3	$3,013,716.00	991.46290161	0.00000000	0.00000000	1.74924246	0.9897136592	989.71365915
CB4	$1,130,143.00	991.46290337	0.00000000	0.00000000	1.74923881	0.9897136646	989.71366455
CB5	$1,130,143.00	991.46290337	0.00000000	0.00000000	1.74923881	0.9897136646	989.71366455
CB6	$1,506,857.67	991.46290970	0.00001327	0.00000000	1.74924285	0.9897136602	989.71366022
R	$100.00	0.00000000	0.00000000	0.00000000	0.00000000	0.0000000000	0.00000000
R_SYN	$0.00	0.00000000	0.00000000	0.00000000	0.00000000	0.0000000000	0.00000000

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
Series: WAMMS.03MS3
Distribution Date: 08/25/2003

Class	Orig Face	Int Rate Accrued	Int Rate Paid	Beg Cert Prin/Not Bal	Curent Int Accrued	Int Shortfall	Unscheduled Int	Int Reimbursed	Total Int Dist
IA1	$300,000,000.00	5.7500000000%	5.7500000000%	$177,813,840.30	$852,024.65	$0.00	$0.00	$0.00	$852,024.65
IA2	$25,000,000.00	5.7500000000%	5.7500000000%	$25,000,000.00	$119,791.67	$0.00	$0.00	$0.00	$119,791.67
IA3	$1,000,000.00	5.5000000000%	5.5000000000%	$1,000,000.00	$4,583.33	$0.00	$0.00	$0.00	$4,583.33
IA4	$46,000,000.00	5.7500000000%	5.7500000000%	$46,000,000.00	$220,416.67	$0.00	$0.00	$0.00	$220,416.67
IA5	$6,992,000.00	5.7500000000%	5.7500000000%	$6,992,000.00	$33,503.33	$0.00	$0.00	$0.00	$33,503.33
IA6	$1,000,000.00	5.5000000000%	5.5000000000%	$1,000,000.00	$4,583.33	$0.00	$0.00	$0.00	$4,583.33
IA7	$1,000,000.00	5.5000000000%	5.5000000000%	$1,000,000.00	$4,583.33	$0.00	$0.00	$0.00	$4,583.33
IA8	$1,000,000.00	5.5000000000%	5.5000000000%	$1,000,000.00	$4,583.33	$0.00	$0.00	$0.00	$4,583.33
IA9	$1,000,000.00	5.5000000000%	5.5000000000%	$1,000,000.00	$4,583.33	$0.00	$0.00	$0.00	$4,583.33
IA10	$1,000,000.00	5.5000000000%	5.5000000000%	$1,000,000.00	$4,583.33	$0.00	$0.00	$0.00	$4,583.33
IA11	$1,000,000.00	5.5000000000%	5.5000000000%	$1,000,000.00	$4,583.33	$0.00	$0.00	$0.00	$4,583.33
IA12	$1,000,000.00	5.5000000000%	5.5000000000%	$1,000,000.00	$4,583.33	$0.00	$0.00	$0.00	$4,583.33
IA13	$1,000,000.00	5.5000000000%	5.5000000000%	$1,000,000.00	$4,583.33	$0.00	$0.00	$0.00	$4,583.33
IA14	$1,000,000.00	5.5000000000%	5.5000000000%	$1,000,000.00	$4,583.33	$0.00	$0.00	$0.00	$4,583.33
IA15	$3,000,000.00	5.7500000000%	5.7500000000%	$3,000,000.00	$14,375.00	$0.00	$0.00	$0.00	$14,375.00
IA16	$3,000,000.00	5.7500000000%	5.7500000000%	$3,000,000.00	$14,375.00	$0.00	$0.00	$0.00	$14,375.00
IA17	$3,000,000.00	5.7500000000%	5.7500000000%	$3,000,000.00	$14,375.00	$0.00	$0.00	$0.00	$14,375.00
IA18	$3,000,000.00	5.7500000000%	5.7500000000%	$3,000,000.00	$14,375.00	$0.00	$0.00	$0.00	$14,375.00
IA19	$1,500,000.00	6.0000000000%	6.0000000000%	$1,500,000.00	$7,500.00	$0.00	$0.00	$0.00	$7,500.00
IA20	$1,500,000.00	5.5000000000%	5.5000000000%	$1,500,000.00	$6,875.00	$0.00	$0.00	$0.00	$6,875.00
IA21	$1,086,956.52	5.7500000000%	5.7500000000%	$1,086,956.52	$5,208.33	$0.00	$0.00	$0.00	$5,208.33
IA22	$50,627,000.00	5.7500000000%	5.7500000000%	$32,494,537.57	$155,702.99	$0.00	$0.00	$0.00	$155,702.99
IA23	$25,059,375.00	4.5000000000%	4.5000000000%	$16,300,031.71	$61,125.12	$0.00	$0.00	$0.00	$61,125.12
IA24	$24,850,000.00	5.7500000000%	5.7500000000%	$24,850,000.00	$119,072.92	$0.00	$0.00	$0.00	$119,072.92
IA25	$11,390,625.00	1.7250000000%	1.7250000000%	$7,409,105.33	$10,650.59	$0.00	$0.00	$0.00	$10,650.59
IA26	$11,390,625.00	6.7750000000%	6.7750000000%	$7,409,105.33	$41,830.57	$0.00	$0.00	$0.00	$41,830.57
IA27	$400,000.00	5.5000000000%	5.5000000000%	$400,000.00	$1,833.33	$0.00	$0.00	$0.00	$1,833.33
IA28	$400,000.00	5.5000000000%	5.5000000000%	$400,000.00	$1,833.33	$0.00	$0.00	$0.00	$1,833.33
IA29	$400,000.00	5.5000000000%	5.5000000000%	$400,000.00	$1,833.33	$0.00	$0.00	$0.00	$1,833.33
IA30	$400,000.00	5.5000000000%	5.5000000000%	$400,000.00	$1,833.33	$0.00	$0.00	$0.00	$1,833.33
IA31	$400,000.00	5.5000000000%	5.5000000000%	$400,000.00	$1,833.33	$0.00	$0.00	$0.00	$1,833.33

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
Series: WAMMS.03MS3
Distribution Date: 08/25/2003

Class	Orig Face	Int Rate Accrued	Int Rate Paid	Beg Cert Prin/Not Bal	Curent Int Accrued	Int Shortfall	Unscheduled Int	Int Reimbursed	Total Int Dist
IA32	$400,000.00	5.5000000000%	5.5000000000%	$400,000.00	$1,833.33	$0.00	$0.00	$0.00	$1,833.33
IA33	$400,000.00	5.5000000000%	5.5000000000%	$400,000.00	$1,833.33	$0.00	$0.00	$0.00	$1,833.33
IA34	$400,000.00	5.5000000000%	5.5000000000%	$400,000.00	$1,833.33	$0.00	$0.00	$0.00	$1,833.33
IA35	$400,000.00	5.5000000000%	5.5000000000%	$400,000.00	$1,833.33	$0.00	$0.00	$0.00	$1,833.33
IA36	$400,000.00	5.5000000000%	5.5000000000%	$400,000.00	$1,833.33	$0.00	$0.00	$0.00	$1,833.33
IA37	$400,000.00	5.5000000000%	5.5000000000%	$400,000.00	$1,833.33	$0.00	$0.00	$0.00	$1,833.33
IA38	$400,000.00	5.5000000000%	5.5000000000%	$400,000.00	$1,833.33	$0.00	$0.00	$0.00	$1,833.33
IA39	$400,000.00	5.5000000000%	5.5000000000%	$400,000.00	$1,833.33	$0.00	$0.00	$0.00	$1,833.33
IA40	$400,000.00	5.5000000000%	5.5000000000%	$400,000.00	$1,833.33	$0.00	$0.00	$0.00	$1,833.33
IA41	$400,000.00	5.5000000000%	5.5000000000%	$400,000.00	$1,833.33	$0.00	$0.00	$0.00	$1,833.33
IA42	$400,000.00	5.5000000000%	5.5000000000%	$400,000.00	$1,833.33	$0.00	$0.00	$0.00	$1,833.33
IA43	$400,000.00	5.5000000000%	5.5000000000%	$400,000.00	$1,833.33	$0.00	$0.00	$0.00	$1,833.33
IA44	$400,000.00	5.5000000000%	5.5000000000%	$400,000.00	$1,833.33	$0.00	$0.00	$0.00	$1,833.33
IA45	$400,000.00	5.5000000000%	5.5000000000%	$400,000.00	$1,833.33	$0.00	$0.00	$0.00	$1,833.33
IA46	$400,000.00	5.5000000000%	5.5000000000%	$400,000.00	$1,833.33	$0.00	$0.00	$0.00	$1,833.33
IA47	$400,000.00	5.5000000000%	5.5000000000%	$400,000.00	$1,833.33	$0.00	$0.00	$0.00	$1,833.33
IA48	$400,000.00	5.5000000000%	5.5000000000%	$400,000.00	$1,833.33	$0.00	$0.00	$0.00	$1,833.33
IA49	$400,000.00	5.5000000000%	5.5000000000%	$400,000.00	$1,833.33	$0.00	$0.00	$0.00	$1,833.33
IA50	$400,000.00	5.5000000000%	5.5000000000%	$400,000.00	$1,833.33	$0.00	$0.00	$0.00	$1,833.33
IA51	$400,000.00	5.5000000000%	5.5000000000%	$400,000.00	$1,833.33	$0.00	$0.00	$0.00	$1,833.33
IA52	$400,000.00	5.5000000000%	5.5000000000%	$400,000.00	$1,833.33	$0.00	$0.00	$0.00	$1,833.33
IA53	$400,000.00	5.5000000000%	5.5000000000%	$400,000.00	$1,833.33	$0.00	$0.00	$0.00	$1,833.33
IA54	$400,000.00	5.5000000000%	5.5000000000%	$400,000.00	$1,833.33	$0.00	$0.00	$0.00	$1,833.33
IA55	$400,000.00	5.5000000000%	5.5000000000%	$400,000.00	$1,833.33	$0.00	$0.00	$0.00	$1,833.33
IA56	$400,000.00	5.5000000000%	5.5000000000%	$400,000.00	$1,833.33	$0.00	$0.00	$0.00	$1,833.33
IA57	$400,000.00	5.5000000000%	5.5000000000%	$400,000.00	$1,833.33	$0.00	$0.00	$0.00	$1,833.33
IA58	$400,000.00	5.5000000000%	5.5000000000%	$400,000.00	$1,833.33	$0.00	$0.00	$0.00	$1,833.33
IA59	$400,000.00	5.5000000000%	5.5000000000%	$400,000.00	$1,833.33	$0.00	$0.00	$0.00	$1,833.33
IA60	$400,000.00	5.5000000000%	5.5000000000%	$400,000.00	$1,833.33	$0.00	$0.00	$0.00	$1,833.33
IA61	$400,000.00	5.5000000000%	5.5000000000%	$400,000.00	$1,833.33	$0.00	$0.00	$0.00	$1,833.33
IA62	$400,000.00	5.5000000000%	5.5000000000%	$400,000.00	$1,833.33	$0.00	$0.00	$0.00	$1,833.33

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
Series: WAMMS.03MS3
Distribution Date: 08/25/2003

Class	Orig Face	Int Rate Accrued	Int Rate Paid	Beg Cert Prin/Not Bal	Curent Int Accrued	Int Shortfall	Unscheduled Int	Int Reimbursed	Total Int Dist
IA63	$600,000.00	5.5000000000%	5.5000000000%	$600,000.00	$2,750.00	$0.00	$0.00	$0.00	$2,750.00
IIA1	$125,395,000.00	5.2500000000%	5.2500000000%	$90,483,877.34	$395,866.96	$0.00	$0.00	$0.00	$395,866.96
IIA2	$52,370,500.00	4.5000000000%	4.5000000000%	$37,790,070.55	$141,712.76	$0.00	$0.00	$0.00	$141,712.76
IIA3	$327,000.00	4.5000000000%	4.5000000000%	$235,960.19	$884.85	$0.00	$0.00	$0.00	$884.85
IIA4	$10,000,000.00	4.5000000000%	4.5000000000%	$7,215,907.91	$27,059.65	$0.00	$0.00	$0.00	$27,059.65
IIA5	$3,500,000.00	5.0000000000%	5.0000000000%	$2,525,567.77	$10,523.20	$0.00	$0.00	$0.00	$10,523.20
IIA6	$10,000,000.00	5.0000000000%	5.0000000000%	$7,215,907.91	$30,066.28	$0.00	$0.00	$0.00	$30,066.28
IX	$6,779,035.00	5.7500000000%	5.7500000000%	$4,490,565.39	$21,517.29	$0.00	$0.00	$0.00	$21,517.29
IIX	$12,486,599.00	5.0000000000%	5.0000000000%	$8,238,772.49	$34,328.22	$0.00	$0.00	$0.00	$34,328.22
IP	$1,101,174.80	0.0000000000%	0.0000000000%	$1,052,023.95	$0.00	$0.00	$0.00	$0.00	$0.00
IIP	$96,394.50	0.0000000000%	0.0000000000%	$94,515.23	$0.00	$0.00	$0.00	$0.00	$0.00
CB1	$9,418,327.00	5.5455848907%	5.5455848907%	$9,337,921.80	$43,153.53	$0.00	$0.00	$0.00	$43,153.53
CB2	$4,520,574.00	5.5455848907%	5.5455848907%	$4,481,981.42	$20,712.67	$0.00	$0.00	$0.00	$20,712.67
CB3	$3,013,716.00	5.5455848907%	5.5455848907%	$2,987,987.61	$13,808.45	$0.00	$0.00	$0.00	$13,808.45
CB4	$1,130,143.00	5.5455848907%	5.5455848907%	$1,120,494.86	$5,178.17	$0.00	$0.00	$0.00	$5,178.17
CB5	$1,130,143.00	5.5455848907%	5.5455848907%	$1,120,494.86	$5,178.17	$0.00	$0.00	$0.00	$5,178.17
CB6	$1,506,857.67	5.5455848907%	5.5455848907%	$1,493,993.49	$6,904.22	$0.00	$0.00	$0.00	$6,904.22
R	$100.00	0.0000000000%	0.0000000000%	$0.00	$0.06	$0.00	$0.00	$0.00	$0.06
R_SYN	$0.00	0.0000000000%	0.0000000000%	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00
Total	$753,428,929.97			$544,016,219.80	$2,562,679.67	$0.00	$0.00	$0.00	$2,562,679.67

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
Series: WAMMS.03MS3
Distribution Date: 08/25/2003
PER $1000 DENOMINATION
Class	Orig Face	Int Rate Accrued	Int Rate Paid	Beg Cert Prin/Not Bal	Curent Int Accrued	Int Shortfall	Unscheduled Int	Int Reimbursed	Total Int Dist
IA1	$300,000,000.00	5.7500000000%	5.7500000000%	592.71280100	2.84008217	0.00000000	0.00000000	0.00000000	2.84008217
IA2	$25,000,000.00	5.7500000000%	5.7500000000%	1,000.00000000	4.79166680	0.00000000	0.00000000	0.00000000	4.79166680
IA3	$1,000,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58333000	0.00000000	0.00000000	0.00000000	4.58333000
IA4	$46,000,000.00	5.7500000000%	5.7500000000%	1,000.00000000	4.79166674	0.00000000	0.00000000	0.00000000	4.79166674
IA5	$6,992,000.00	5.7500000000%	5.7500000000%	1,000.00000000	4.79166619	0.00000000	0.00000000	0.00000000	4.79166619
IA6	$1,000,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58333000	0.00000000	0.00000000	0.00000000	4.58333000
IA7	$1,000,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58333000	0.00000000	0.00000000	0.00000000	4.58333000
IA8	$1,000,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58333000	0.00000000	0.00000000	0.00000000	4.58333000
IA9	$1,000,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58333000	0.00000000	0.00000000	0.00000000	4.58333000
IA10	$1,000,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58333000	0.00000000	0.00000000	0.00000000	4.58333000
IA11	$1,000,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58333000	0.00000000	0.00000000	0.00000000	4.58333000
IA12	$1,000,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58333000	0.00000000	0.00000000	0.00000000	4.58333000
IA13	$1,000,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58333000	0.00000000	0.00000000	0.00000000	4.58333000
IA14	$1,000,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58333000	0.00000000	0.00000000	0.00000000	4.58333000
IA15	$3,000,000.00	5.7500000000%	5.7500000000%	1,000.00000000	4.79166667	0.00000000	0.00000000	0.00000000	4.79166667
IA16	$3,000,000.00	5.7500000000%	5.7500000000%	1,000.00000000	4.79166667	0.00000000	0.00000000	0.00000000	4.79166667
IA17	$3,000,000.00	5.7500000000%	5.7500000000%	1,000.00000000	4.79166667	0.00000000	0.00000000	0.00000000	4.79166667
IA18	$3,000,000.00	5.7500000000%	5.7500000000%	1,000.00000000	4.79166667	0.00000000	0.00000000	0.00000000	4.79166667
IA19	$1,500,000.00	6.0000000000%	6.0000000000%	1,000.00000000	5.00000000	0.00000000	0.00000000	0.00000000	5.00000000
IA20	$1,500,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58333333	0.00000000	0.00000000	0.00000000	4.58333333
IA21	$1,086,956.52	5.7500000000%	5.7500000000%	1,000.00000000	4.79166361	0.00000000	0.00000000	0.00000000	4.79166361
IA22	$50,627,000.00	5.7500000000%	5.7500000000%	641.84205207	3.07549312	0.00000000	0.00000000	0.00000000	3.07549312
IA23	$25,059,375.00	4.5000000000%	4.5000000000%	650.45643437	2.43921167	0.00000000	0.00000000	0.00000000	2.43921167
IA24	$24,850,000.00	5.7500000000%	5.7500000000%	1,000.00000000	4.79166680	0.00000000	0.00000000	0.00000000	4.79166680
IA25	$11,390,625.00	1.7250000000%	1.7250000000%	650.45643501	0.93503122	0.00000000	0.00000000	0.00000000	0.93503122
IA26	$11,390,625.00	6.7750000000%	6.7750000000%	650.45643501	3.67236829	0.00000000	0.00000000	0.00000000	3.67236829
IA27	$400,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58332500	0.00000000	0.00000000	0.00000000	4.58332500
IA28	$400,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58332500	0.00000000	0.00000000	0.00000000	4.58332500
IA29	$400,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58332500	0.00000000	0.00000000	0.00000000	4.58332500
IA30	$400,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58332500	0.00000000	0.00000000	0.00000000	4.58332500
IA31	$400,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58332500	0.00000000	0.00000000	0.00000000	4.58332500

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
Series: WAMMS.03MS3
Distribution Date: 08/25/2003
PER $1000 DENOMINATION
Class	Orig Face	Int Rate Accrued	Int Rate Paid	Beg Cert Prin/Not Bal	Curent Int Accrued	Int Shortfall	Unscheduled Int	Int Reimbursed	Total Int Dist
IA32	$400,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58332500	0.00000000	0.00000000	0.00000000	4.58332500
IA33	$400,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58332500	0.00000000	0.00000000	0.00000000	4.58332500
IA34	$400,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58332500	0.00000000	0.00000000	0.00000000	4.58332500
IA35	$400,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58332500	0.00000000	0.00000000	0.00000000	4.58332500
IA36	$400,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58332500	0.00000000	0.00000000	0.00000000	4.58332500
IA37	$400,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58332500	0.00000000	0.00000000	0.00000000	4.58332500
IA38	$400,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58332500	0.00000000	0.00000000	0.00000000	4.58332500
IA39	$400,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58332500	0.00000000	0.00000000	0.00000000	4.58332500
IA40	$400,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58332500	0.00000000	0.00000000	0.00000000	4.58332500
IA41	$400,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58332500	0.00000000	0.00000000	0.00000000	4.58332500
IA42	$400,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58332500	0.00000000	0.00000000	0.00000000	4.58332500
IA43	$400,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58332500	0.00000000	0.00000000	0.00000000	4.58332500
IA44	$400,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58332500	0.00000000	0.00000000	0.00000000	4.58332500
IA45	$400,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58332500	0.00000000	0.00000000	0.00000000	4.58332500
IA46	$400,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58332500	0.00000000	0.00000000	0.00000000	4.58332500
IA47	$400,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58332500	0.00000000	0.00000000	0.00000000	4.58332500
IA48	$400,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58332500	0.00000000	0.00000000	0.00000000	4.58332500
IA49	$400,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58332500	0.00000000	0.00000000	0.00000000	4.58332500
IA50	$400,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58332500	0.00000000	0.00000000	0.00000000	4.58332500
IA51	$400,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58332500	0.00000000	0.00000000	0.00000000	4.58332500
IA52	$400,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58332500	0.00000000	0.00000000	0.00000000	4.58332500
IA53	$400,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58332500	0.00000000	0.00000000	0.00000000	4.58332500
IA54	$400,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58332500	0.00000000	0.00000000	0.00000000	4.58332500
IA55	$400,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58332500	0.00000000	0.00000000	0.00000000	4.58332500
IA56	$400,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58332500	0.00000000	0.00000000	0.00000000	4.58332500
IA57	$400,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58332500	0.00000000	0.00000000	0.00000000	4.58332500
IA58	$400,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58332500	0.00000000	0.00000000	0.00000000	4.58332500
IA59	$400,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58332500	0.00000000	0.00000000	0.00000000	4.58332500
IA60	$400,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58332500	0.00000000	0.00000000	0.00000000	4.58332500
IA61	$400,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58332500	0.00000000	0.00000000	0.00000000	4.58332500
IA62	$400,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58332500	0.00000000	0.00000000	0.00000000	4.58332500

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
Series: WAMMS.03MS3
Distribution Date: 08/25/2003
PER $1000 DENOMINATION
Class	Orig Face	Int Rate Accrued	Int Rate Paid	Beg Cert Prin/Not Bal	Curent Int Accrued	Int Shortfall	Unscheduled Int	Int Reimbursed	Total Int Dist
IA63	$600,000.00	5.5000000000%	5.5000000000%	1,000.00000000	4.58333333	0.00000000	0.00000000	0.00000000	4.58333333
IIA1	$125,395,000.00	5.2500000000%	5.2500000000%	721.59079182	3.15695969	0.00000000	0.00000000	0.00000000	3.15695969
IIA2	$52,370,500.00	4.5000000000%	4.5000000000%	721.59079157	2.70596538	0.00000000	0.00000000	0.00000000	2.70596538
IIA3	$327,000.00	4.5000000000%	4.5000000000%	721.59079511	2.70596330	0.00000000	0.00000000	0.00000000	2.70596330
IIA4	$10,000,000.00	4.5000000000%	4.5000000000%	721.59079100	2.70596500	0.00000000	0.00000000	0.00000000	2.70596500
IIA5	$3,500,000.00	5.0000000000%	5.0000000000%	721.59079143	3.00662857	0.00000000	0.00000000	0.00000000	3.00662857
IIA6	$10,000,000.00	5.0000000000%	5.0000000000%	721.59079100	3.00662800	0.00000000	0.00000000	0.00000000	3.00662800
IX	$6,779,035.00	5.7500000000%	5.7500000000%	662.41956119	3.17409336	0.00000000	0.00000000	0.00000000	3.17409336
IIX	$12,486,599.00	5.0000000000%	5.0000000000%	659.80916741	2.74920497	0.00000000	0.00000000	0.00000000	2.74920497
IP	$1,101,174.80	0.0000000000%	0.0000000000%	955.36507919	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000
IIP	$96,394.50	0.0000000000%	0.0000000000%	980.50438562	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000
CB1	$9,418,327.00	5.5455848907%	5.5455848907%	991.46289994	4.58186788	0.00000000	0.00000000	0.00000000	4.58186788
CB2	$4,520,574.00	5.5455848907%	5.5455848907%	991.46290272	4.58186726	0.00000000	0.00000000	0.00000000	4.58186726
CB3	$3,013,716.00	5.5455848907%	5.5455848907%	991.46290161	4.58186836	0.00000000	0.00000000	0.00000000	4.58186836
CB4	$1,130,143.00	5.5455848907%	5.5455848907%	991.46290337	4.58187150	0.00000000	0.00000000	0.00000000	4.58187150
CB5	$1,130,143.00	5.5455848907%	5.5455848907%	991.46290337	4.58187150	0.00000000	0.00000000	0.00000000	4.58187150
CB6	$1,506,857.67	5.5455848907%	5.5455848907%	991.46290970	4.58186605	0.00000000	0.00000000	0.00000000	4.58186605
R	$100.00	0.0000000000%	0.0000000000%	0.00000000	0.60000000	0.00000000	0.00000000	0.00000000	0.60000000
R_SYN	$0.00	0.0000000000%	0.0000000000%	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
MASTER SERVICING
MORTGAGE PASS-THROUGH CERTIFICATES
08/2003 DISTRIBUTION REPORT
SERIES: WAMMS 03MS3 WEIGHTED AVERAGE PC RATE: 5.65280%
POOL NUMBER: Group 1(2039,2040)
ISSUE DATE: 02/28/2003
CERTIFICATE BALANCE AT ISSUE: $753,428,929.97
	TOTAL NUMBER OF MORTAGES	CERTIFICATE ACCOUNT ACTIVITY (@ PCRATE)	CERTIFICATE BALANCE OUTSTANDING
BALANCES FROM LAST FISCAL MONTH-END:	1223		$544,016,219.78
PRINCIPAL POOL COLLECTION(S):
Scheduled Principal Collection Due Current Month		$968,097.59
Unscheduled Principal Collection/Reversals		$284,206.71
Liquidations-in-full	148	$67,130,507.74
Net principal Distributed		$68,382,812.04	-$68,382,812.04

CAPITAL LOSS (PRINCIPAL WRITTEN OFF):			$0.00

BALANCE CURRENT FISCAL MONTH-END:	1075		$475,633,407.74

SCHEDULED INTEREST AT MORTGAGE RATE:		$2,820,453.71

UNSCHEDULED INTEREST AT MORTGAGE RATE:
Unscheduled Interest Collection/Reversals		$0.00
Interest Uncollected on Liquidation		$0.00
Interest Uncollected on Non-Earning Assets		$0.00
Net Unscheduled Interest Distributed		$0.00

OTHER:
Loan Conversion Fees		$0.00
Expense Reimbursements		$0.00
Gain on Liquidations		$0.00
Hazard Insurance Premium Refunds		$0.00
Net Other Distributions		$0.00

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
MASTER SERVICING
MORTGAGE PASS-THROUGH CERTIFICATES
08/2003 DISTRIBUTION REPORT
	TOTAL NUMBER OF MORTAGES	CERTIFICATE ACCOUNT ACTIVITY (@ PCRATE)	CERTIFICATE BALANCE OUTSTANDING
SCHEDULED SERVICING FEE EXPENSES:		$257,774.04

UNSCHEDULED SERVICING FEES:
Unscheduled Service Fee Collections/Reversals		$0.00
Servicing Fees Uncollected on Liquidation		$0.00
Servicing Fees Uncollected/Non-Earning Assets		$0.00
Net Unscheduled Service Fees Distributed		$0.00

MISCELLANEOUS EXPENSES:		$0.00

NET FUNDS DISTRIBUTED:		$70,945,491.71

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
MASTER SERVICING
MORTGAGE PASS-THROUGH CERTIFICATES
08/2003 DISTRIBUTION REPORT
SERIES: WAMMS 03MS3 WEIGHTED AVERAGE PC RATE: 5.80033%
POOL NUMBER: 2039
ISSUE DATE: 02/28/2003
CERTIFICATE BALANCE AT ISSUE: $546,036,501.19
	TOTAL NUMBER OF MORTAGES	CERTIFICATE ACCOUNT ACTIVITY (@ PCRATE)	CERTIFICATE BALANCE OUTSTANDING
BALANCES FROM LAST FISCAL MONTH-END:	885		$392,855,381.10
PRINCIPAL POOL COLLECTION(S):
Scheduled Principal Collection Due Current Month		$391,116.52
Unscheduled Principal Collection/Reversals		$144,094.18
Liquidations-in-full	113	$50,643,273.65
Net principal Distributed		$51,178,484.35	-$51,178,484.35

CAPITAL LOSS (PRINCIPAL WRITTEN OFF):			$0.00

BALANCE CURRENT FISCAL MONTH-END:	772		$341,676,896.75

SCHEDULED INTEREST AT MORTGAGE RATE:		$2,090,522.46

UNSCHEDULED INTEREST AT MORTGAGE RATE:
Unscheduled Interest Collection/Reversals		$0.00
Interest Uncollected on Liquidation		$0.00
Interest Uncollected on Non-Earning Assets		$0.00
Net Unscheduled Interest Distributed		$0.00

OTHER:
Loan Conversion Fees		$0.00
Expense Reimbursements		$0.00
Gain on Liquidations		$0.00
Hazard Insurance Premium Refunds		$0.00
Net Other Distributions		$0.00

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
MASTER SERVICING
MORTGAGE PASS-THROUGH CERTIFICATES
08/2003 DISTRIBUTION REPORT
	TOTAL NUMBER OF MORTAGES	CERTIFICATE ACCOUNT ACTIVITY (@ PCRATE)	CERTIFICATE BALANCE OUTSTANDING
SCHEDULED SERVICING FEE EXPENSES:		$191,614.11

UNSCHEDULED SERVICING FEES:
Unscheduled Service Fee Collections/Reversals		$0.00
Servicing Fees Uncollected on Liquidation		$0.00
Servicing Fees Uncollected/Non-Earning Assets		$0.00
Net Unscheduled Service Fees Distributed		$0.00

MISCELLANEOUS EXPENSES:		$0.00

NET FUNDS DISTRIBUTED:		$53,077,392.70

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
MASTER SERVICING
MORTGAGE PASS-THROUGH CERTIFICATES
08/2003 DISTRIBUTION REPORT
SERIES: WAMMS 03MS3 WEIGHTED AVERAGE PC RATE: 5.26939%
POOL NUMBER: 2040
ISSUE DATE: 02/28/2003
CERTIFICATE BALANCE AT ISSUE: $207,392,428.78
	TOTAL NUMBER OF MORTAGES	CERTIFICATE ACCOUNT ACTIVITY (@ PCRATE)	CERTIFICATE BALANCE OUTSTANDING
BALANCES FROM LAST FISCAL MONTH-END:	338		$151,160,838.68
PRINCIPAL POOL COLLECTION(S):
Scheduled Principal Collection Due Current Month		$576,981.07
Unscheduled Principal Collection/Reversals		$140,112.53
Liquidations-in-full	35	$16,487,234.09
Net principal Distributed		$17,204,327.69	-$17,204,327.69

CAPITAL LOSS (PRINCIPAL WRITTEN OFF):			$0.00

BALANCE CURRENT FISCAL MONTH-END:	303		$133,956,510.99

SCHEDULED INTEREST AT MORTGAGE RATE:		$729,931.25

UNSCHEDULED INTEREST AT MORTGAGE RATE:
Unscheduled Interest Collection/Reversals		$0.00
Interest Uncollected on Liquidation		$0.00
Interest Uncollected on Non-Earning Assets		$0.00
Net Unscheduled Interest Distributed		$0.00

OTHER:
Loan Conversion Fees		$0.00
Expense Reimbursements		$0.00
Gain on Liquidations		$0.00
Hazard Insurance Premium Refunds		$0.00
Net Other Distributions		$0.00

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
MASTER SERVICING
MORTGAGE PASS-THROUGH CERTIFICATES
08/2003 DISTRIBUTION REPORT
	TOTAL NUMBER OF MORTAGES	CERTIFICATE ACCOUNT ACTIVITY (@ PCRATE)	CERTIFICATE BALANCE OUTSTANDING
SCHEDULED SERVICING FEE EXPENSES:		$66,159.93

UNSCHEDULED SERVICING FEES:
Unscheduled Service Fee Collections/Reversals		$0.00
Servicing Fees Uncollected on Liquidation		$0.00
Servicing Fees Uncollected/Non-Earning Assets		$0.00
Net Unscheduled Service Fees Distributed		$0.00

MISCELLANEOUS EXPENSES:		$0.00

NET FUNDS DISTRIBUTED:		$17,868,099.01

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
MASTER SERVICING
MORTGAGE PASS-THROUGH CERTIFICATES
08/2003 DISTRIBUTION REPORT
SERIES: WAMMS 03MS3 WEIGHTED AVERAGE PC RATE: 5.65280%
POOL NUMBER: ALL
ISSUE DATE: 02/28/2003
CERTIFICATE BALANCE AT ISSUE: $753,428,929.97
	TOTAL NUMBER OF MORTAGES	CERTIFICATE ACCOUNT ACTIVITY (@ PCRATE)	CERTIFICATE BALANCE OUTSTANDING
BALANCES FROM LAST FISCAL MONTH-END:	1223		$544,016,219.78
PRINCIPAL POOL COLLECTION(S):
Scheduled Principal Collection Due Current Month		$968,097.59
Unscheduled Principal Collection/Reversals		$284,206.71
Liquidations-in-full	148	$67,130,507.74
Net principal Distributed		$68,382,812.04	-$68,382,812.04

CAPITAL LOSS (PRINCIPAL WRITTEN OFF):			$0.00

BALANCE CURRENT FISCAL MONTH-END:	1075		$475,633,407.74

SCHEDULED INTEREST AT MORTGAGE RATE:		$2,820,453.71

UNSCHEDULED INTEREST AT MORTGAGE RATE:
Unscheduled Interest Collection/Reversals		$0.00
Interest Uncollected on Liquidation		$0.00
Interest Uncollected on Non-Earning Assets		$0.00
Net Unscheduled Interest Distributed		$0.00

OTHER:
Loan Conversion Fees		$0.00
Expense Reimbursements		$0.00
Gain on Liquidations		$0.00
Hazard Insurance Premium Refunds		$0.00
Net Other Distributions		$0.00

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
MASTER SERVICING
MORTGAGE PASS-THROUGH CERTIFICATES
08/2003 DISTRIBUTION REPORT
	TOTAL NUMBER OF MORTAGES	CERTIFICATE ACCOUNT ACTIVITY (@ PCRATE)	CERTIFICATE BALANCE OUTSTANDING
SCHEDULED SERVICING FEE EXPENSES:		$257,774.04

UNSCHEDULED SERVICING FEES:
Unscheduled Service Fee Collections/Reversals		$0.00
Servicing Fees Uncollected on Liquidation		$0.00
Servicing Fees Uncollected/Non-Earning Assets		$0.00
Net Unscheduled Service Fees Distributed		$0.00

MISCELLANEOUS EXPENSES:		$0.00

NET FUNDS DISTRIBUTED:		$70,945,491.71

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
Series: WAMMS.03MS3
Distribution Date: 08/25/2003

Distribution by Group
Pool ID		Principal		Interest		Total
Group 1(2039,2040)		$68,382,812.04		$2,562,679.67		$70,945,491.71
Pool - 2039		$51,178,484.35		$1,898,908.35		$53,077,392.70
Pool - 2040		$17,204,327.69		$663,771.32		$17,868,099.01
Aggregate		$68,382,812.04		$2,562,679.67		$70,945,491.71

Number of Loans and Aggregate Principal Balance By Group
Pool ID	Beg Bal	Beg Count	Paid Off / Liq Count	Rem Count	Sched Prin End Bal	Sched Prin	Prin PrePay / Liq	Unsched Prin / Rev	Total Prin
Group 1(2039,2040)	$544,016,219.78	1223	148	1075	$475,633,407.74	$968,097.59	$67,130,507.74	$284,206.71	$68,382,812.04
Pool - 2039	$392,855,381.10	885	113	772	$341,676,896.75	$391,116.52	$50,643,273.65	$144,094.18	$51,178,484.35
Pool - 2040	$151,160,838.68	338	35	303	$133,956,510.99	$576,981.07	$16,487,234.09	$140,112.53	$17,204,327.69
Aggregate	$544,016,219.78	1223	148	1075	$475,633,407.74	$968,097.59	$67,130,507.74	$284,206.71	$68,382,812.04

Delinquency Information by Group
Pool ID	1 Month Count	Sched End Balance	2 Months Count	Sched End Balance	3 Months Count	Sched End Balance	4 Months Count	Sched End Balance
Group 1(2039,2040)	12	$4,701,118.38	0	$0.00	1	$421,558.29	1	$493,495.48
Pool - 2039	10	$3,890,848.86	0	$0.00	1	$421,558.29	1	$493,495.48
Pool - 2040	2	$810,269.52	0	$0.00	0	$0.00	0	$0.00
Aggregate	12	$4,701,118.38	0	$0.00	1	$421,558.29	1	$493,495.48

Foreclosure and REO Information by Group
Pool ID		Foreclosure Count		Sched End Balance		REO Count		Sched End Balance
Group 1(2039,2040)		0		$0.00		0		$0.00
Pool - 2039		0		$0.00		0		$0.00
Pool - 2040		0		$0.00		0		$0.00
Aggregate		0		$0.00		0		$0.00

Aggregate Loss Amounts by Group
Pool ID			Count			Loss Amount
Group 1(2039,2040)			0			$0.00
Aggregate			0			$0.00

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
Series: WAMMS.03MS3
Distribution Date: 08/25/2003

INSURANCE RESERVES - Group 1(2039,2040)
Insurance Type	Original Balance	Claims In Progress	Claims Paid	Coverage Adjustments	Coverage Remaining
MPI	$0.00	$0.00	$0.00	$0.00	$0.00
Special Hazard	$0.00	$0.00	$0.00	$0.00	$0.00
Bankruptcy Bond
Single-Units	$0.00	$0.00	$0.00	$0.00	$0.00
Multi-Units	$0.00	$0.00	$0.00	$0.00	$0.00
Mortgage Repurchase	$0.00	$0.00	$0.00	$0.00	$0.00

INSURANCE RESERVES - Aggregate
Insurance Type	Original Balance	Claims In Progress	Claims Paid	Coverage Adjustments	Coverage Remaining
MPI	$0.00	$0.00	$0.00	$0.00	$0.00
Special Hazard	$0.00	$0.00	$0.00	$0.00	$0.00
Bankruptcy Bond
Single-Units	$0.00	$0.00	$0.00	$0.00	$0.00
Multi-Units	$0.00	$0.00	$0.00	$0.00	$0.00
Mortgage Repurchase	$0.00	$0.00	$0.00	$0.00	$0.00

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
Series: WAMMS.03MS3
Distribution Date: 08/25/2003

The Group C-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 Group I and II Certificates. The "Prospectus Supplement" is that certain Prospectus Supplement, dated February 26, 2003 to that certain Prospectus Supplement, dated November 21, 2002, to which certain Group I and II Certificates were offered. The Special Hazard, Bankruptcy, and Fraud coverage (collectively, "Credit Enhancements") provided by the C-B certificates provide coverage to the Group I and II Loans, subject to the conditions and limitations to payment specified thereunder.



The Class Principal Balances of each Class of the Class CB1,CB2,CB3,CB4,CB5,CB6 Certificatesimmediately after the principal and interest distribution on 200308 are as follows:

Class			Class Principal Balance
CB1			$9,321,446.87
CB2			$4,474,073.84
CB3			$2,982,715.89
CB4			$1,118,517.97
CB5			$1,118,517.97
CB6			$1,491,357.62
Total			$20,506,630.15
Capitalized items used but not defined herein have the meanings ascribed to them in the Prospectus Supplement.
The amount of the special hazard coverage, bankruptcy coverage, and fraud coverage, as of the above referenced distribution date, is $0.00, $0.00, $0.00 respectively, and such coverages are referred to in the table above under the column "Insurance Type" as "special hazard," "bankruptcy bond," and "mortgage repurchase," respectively. However, no policy of insurance exists for any such coverage, notwithstanding the reference to "insurance."

WASHINGTON MUTUAL MSC MORT PASS THROUGH CERT SER 2003-MS3 8-K