WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
Series: WAMMS.03AR3
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
IA	939336G23	$114,923,400.00	$112,315,515.30	3.5616350361%	3.5616350361%	$333,355.73	$5,015,559.67	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$5,348,915.40	$107,299,955.63
IIA1	939336G31	$23,850,000.00	$23,840,387.38	5.0949862217%	5.0949862217%	$101,222.04	$395,747.30	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$496,969.34	$23,444,640.08
IIA2	939336G49	$281,242,600.00	$281,129,246.67	4.0429862217%	4.0429862217%	$947,168.06	$4,666,708.58	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$5,613,876.64	$276,462,538.09
IIIA	939336G56	$54,528,100.00	$54,389,715.19	4.8096654700%	4.8096654700%	$217,996.95	$449,799.33	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$667,796.28	$53,939,915.86
IVA	939336G64	$110,100,000.00	$109,697,633.05	5.0558180788%	5.0558180788%	$462,176.06	$1,186,420.39	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,648,596.45	$108,511,212.66
VA	939336G72	$26,677,400.00	$26,660,215.36	5.2009707330%	5.2009707330%	$115,549.17	$1,339,130.56	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$1,454,679.73	$25,321,084.80
IX	939336G80	$114,923,400.00	$112,315,515.30	1.2280000000%	1.2280000000%	$114,936.21	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$114,936.21	$107,299,955.63
IIX	939336G98	$281,242,600.00	$281,129,246.67	1.0520000000%	1.0520000000%	$246,456.64	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$246,456.64	$276,462,538.09
M	939336H22	$27,509,500.00	$27,503,599.62	5.0097041353%	5.0097041353%	$114,820.75	$5,939.30	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$120,760.04	$27,497,660.32
B1	939336H30	$12,565,900.00	$12,563,204.80	5.0097041353%	5.0097041353%	$52,448.28	$2,712.98	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$55,161.26	$12,560,491.82
B2	939336H48	$9,509,600.00	$9,507,560.33	5.0097041353%	5.0097041353%	$39,691.72	$2,053.12	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$41,744.84	$9,505,507.21
B3	939336H55	$6,792,400.00	$6,790,943.13	5.0097041353%	5.0097041353%	$28,350.51	$1,466.48	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$29,816.99	$6,789,476.65
B4	939336H71	$7,132,100.00	$7,130,570.27	5.0097041353%	5.0097041353%	$29,768.37	$1,539.82	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$31,308.19	$7,129,030.45
B5	939336H89	$2,377,400.00	$2,376,890.08	5.0097041353%	5.0097041353%	$9,922.93	$513.28	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$10,436.21	$2,376,376.80
B6	939336H97	$2,037,990.89	$2,037,553.77	5.0097041353%	5.0097041353%	$8,506.28	$440.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$8,946.29	$2,037,113.77
R	939336H63	$100.00	$0.00	0.0000000000%	0.0000000000%	$0.13	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.13	$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		$679,246,490.89	$675,943,034.95			$2,822,369.83	$13,068,030.80	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$15,890,400.63	$662,875,004.15

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
Series: WAMMS.03AR3
Distribution Date: 08/25/2003

Class	Orig Face	Beg Bal	Prin Loss	Deferred Interest	Total Prin	End Cert Pct	End Cert Bal
IA	$114,923,400.00	$112,315,515.30	$0.00	$0.00	$5,015,559.67	0.9336649945	$107,299,955.63
IIA1	$23,850,000.00	$23,840,387.38	$0.00	$0.00	$395,747.30	0.9830037769	$23,444,640.08
IIA2	$281,242,600.00	$281,129,246.67	$0.00	$0.00	$4,666,708.58	0.9830037771	$276,462,538.09
IIIA	$54,528,100.00	$54,389,715.19	$0.00	$0.00	$449,799.33	0.9892131921	$53,939,915.86
IVA	$110,100,000.00	$109,697,633.05	$0.00	$0.00	$1,186,420.39	0.9855695973	$108,511,212.66
VA	$26,677,400.00	$26,660,215.36	$0.00	$0.00	$1,339,130.56	0.9491586436	$25,321,084.80
IX	$114,923,400.00	$112,315,515.30	$0.00	$0.00	$0.00	0.9336649945	$107,299,955.63
IIX	$281,242,600.00	$281,129,246.67	$0.00	$0.00	$0.00	0.9830037771	$276,462,538.09
M	$27,509,500.00	$27,503,599.62	$0.00	$0.00	$5,939.30	0.9995696149	$27,497,660.32
B1	$12,565,900.00	$12,563,204.80	$0.00	$0.00	$2,712.98	0.9995696146	$12,560,491.82
B2	$9,509,600.00	$9,507,560.33	$0.00	$0.00	$2,053.12	0.9995696149	$9,505,507.21
B3	$6,792,400.00	$6,790,943.13	$0.00	$0.00	$1,466.48	0.9995696146	$6,789,476.65
B4	$7,132,100.00	$7,130,570.27	$0.00	$0.00	$1,539.82	0.9995696148	$7,129,030.45
B5	$2,377,400.00	$2,376,890.08	$0.00	$0.00	$513.28	0.9995696139	$2,376,376.80
B6	$2,037,990.89	$2,037,553.77	$0.00	$0.00	$440.00	0.9995696153	$2,037,113.77
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	$679,246,490.89	$675,943,034.95	$0.00	$0.00	$13,068,030.80	0.9758975763	$662,875,004.15

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
Series: WAMMS.03AR3
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
IA	$114,923,400.00	977.30762665	0.00000000	0.00000000	43.64263214	0.9336649945	933.66499451
IIA1	$23,850,000.00	999.59695514	0.00000000	0.00000000	16.59317820	0.9830037769	983.00377694
IIA2	$281,242,600.00	999.59695533	0.00000000	0.00000000	16.59317820	0.9830037771	983.00377713
IIIA	$54,528,100.00	997.46213769	0.00000000	0.00000000	8.24894559	0.9892131921	989.21319210
IVA	$110,100,000.00	996.34544096	0.00000000	0.00000000	10.77584369	0.9855695973	985.56959728
VA	$26,677,400.00	999.35583528	0.00000000	0.00000000	50.19719163	0.9491586436	949.15864365
IX	$114,923,400.00	977.30762665	0.00000000	0.00000000	0.00000000	0.9336649945	933.66499451
IIX	$281,242,600.00	999.59695533	0.00000000	0.00000000	0.00000000	0.9830037771	983.00377713
M	$27,509,500.00	999.78551482	0.00000000	0.00000000	0.21589996	0.9995696149	999.56961486
B1	$12,565,900.00	999.78551477	0.00000000	0.00000000	0.21590017	0.9995696146	999.56961459
B2	$9,509,600.00	999.78551464	0.00000000	0.00000000	0.21589972	0.9995696149	999.56961492
B3	$6,792,400.00	999.78551469	0.00000000	0.00000000	0.21590012	0.9995696146	999.56961457
B4	$7,132,100.00	999.78551479	0.00000000	0.00000000	0.21589995	0.9995696148	999.56961484
B5	$2,377,400.00	999.78551359	0.00000000	0.00000000	0.21589972	0.9995696139	999.56961386
B6	$2,037,990.89	999.78551425	0.00000000	0.00000000	0.21589890	0.9995696153	999.56961535
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.03AR3
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
IA	$114,923,400.00	3.5616350361%	3.5616350361%	$112,315,515.30	$333,355.73	$0.00	$0.00	$0.00	$333,355.73
IIA1	$23,850,000.00	5.0949862217%	5.0949862217%	$23,840,387.38	$101,222.04	$0.00	$0.00	$0.00	$101,222.04
IIA2	$281,242,600.00	4.0429862217%	4.0429862217%	$281,129,246.67	$947,168.06	$0.00	$0.00	$0.00	$947,168.06
IIIA	$54,528,100.00	4.8096654700%	4.8096654700%	$54,389,715.19	$217,996.95	$0.00	$0.00	$0.00	$217,996.95
IVA	$110,100,000.00	5.0558180788%	5.0558180788%	$109,697,633.05	$462,176.06	$0.00	$0.00	$0.00	$462,176.06
VA	$26,677,400.00	5.2009707330%	5.2009707330%	$26,660,215.36	$115,549.17	$0.00	$0.00	$0.00	$115,549.17
IX	$114,923,400.00	1.2280000000%	1.2280000000%	$112,315,515.30	$114,936.21	$0.00	$0.00	$0.00	$114,936.21
IIX	$281,242,600.00	1.0520000000%	1.0520000000%	$281,129,246.67	$246,456.64	$0.00	$0.00	$0.00	$246,456.64
M	$27,509,500.00	5.0097041353%	5.0097041353%	$27,503,599.62	$114,820.75	$0.00	$0.00	$0.00	$114,820.75
B1	$12,565,900.00	5.0097041353%	5.0097041353%	$12,563,204.80	$52,448.28	$0.00	$0.00	$0.00	$52,448.28
B2	$9,509,600.00	5.0097041353%	5.0097041353%	$9,507,560.33	$39,691.72	$0.00	$0.00	$0.00	$39,691.72
B3	$6,792,400.00	5.0097041353%	5.0097041353%	$6,790,943.13	$28,350.51	$0.00	$0.00	$0.00	$28,350.51
B4	$7,132,100.00	5.0097041353%	5.0097041353%	$7,130,570.27	$29,768.37	$0.00	$0.00	$0.00	$29,768.37
B5	$2,377,400.00	5.0097041353%	5.0097041353%	$2,376,890.08	$9,922.93	$0.00	$0.00	$0.00	$9,922.93
B6	$2,037,990.89	5.0097041353%	5.0097041353%	$2,037,553.77	$8,506.28	$0.00	$0.00	$0.00	$8,506.28
R	$100.00	0.0000000000%	0.0000000000%	$0.00	$0.13	$0.00	$0.00	$0.00	$0.13
R_SYN	$0.00	0.0000000000%	0.0000000000%	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00
Total	$679,246,490.89			$675,943,034.95	$2,822,369.83	$0.00	$0.00	$0.00	$2,822,369.83

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
Series: WAMMS.03AR3
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
IA	$114,923,400.00	3.5616350361%	3.5616350361%	977.30762665	2.90067758	0.00000000	0.00000000	0.00000000	2.90067758
IIA1	$23,850,000.00	5.0949862217%	5.0949862217%	999.59695514	4.24411069	0.00000000	0.00000000	0.00000000	4.24411069
IIA2	$281,242,600.00	4.0429862217%	4.0429862217%	999.59695533	3.36779727	0.00000000	0.00000000	0.00000000	3.36779727
IIIA	$54,528,100.00	4.8096654700%	4.8096654700%	997.46213769	3.99788274	0.00000000	0.00000000	0.00000000	3.99788274
IVA	$110,100,000.00	5.0558180788%	5.0558180788%	996.34544096	4.19778438	0.00000000	0.00000000	0.00000000	4.19778438
VA	$26,677,400.00	5.2009707330%	5.2009707330%	999.35583528	4.33135051	0.00000000	0.00000000	0.00000000	4.33135051
IX	$114,923,400.00	1.2280000000%	1.2280000000%	977.30762665	1.00011147	0.00000000	0.00000000	0.00000000	1.00011147
IIX	$281,242,600.00	1.0520000000%	1.0520000000%	999.59695533	0.87631333	0.00000000	0.00000000	0.00000000	0.87631333
M	$27,509,500.00	5.0097041353%	5.0097041353%	999.78551482	4.17385812	0.00000000	0.00000000	0.00000000	4.17385812
B1	$12,565,900.00	5.0097041353%	5.0097041353%	999.78551477	4.17385782	0.00000000	0.00000000	0.00000000	4.17385782
B2	$9,509,600.00	5.0097041353%	5.0097041353%	999.78551464	4.17385800	0.00000000	0.00000000	0.00000000	4.17385800
B3	$6,792,400.00	5.0097041353%	5.0097041353%	999.78551469	4.17385755	0.00000000	0.00000000	0.00000000	4.17385755
B4	$7,132,100.00	5.0097041353%	5.0097041353%	999.78551479	4.17385763	0.00000000	0.00000000	0.00000000	4.17385763
B5	$2,377,400.00	5.0097041353%	5.0097041353%	999.78551359	4.17385800	0.00000000	0.00000000	0.00000000	4.17385800
B6	$2,037,990.89	5.0097041353%	5.0097041353%	999.78551425	4.17385575	0.00000000	0.00000000	0.00000000	4.17385575
R	$100.00	0.0000000000%	0.0000000000%	0.00000000	1.30000000	0.00000000	0.00000000	0.00000000	1.30000000
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 03AR3 WEIGHTED AVERAGE PC RATE: 5.01055%
POOL NUMBER: Group 1(2127,2128,2129,2130,2131)
ISSUE DATE: 06/26/2003
CERTIFICATE BALANCE AT ISSUE: $679,246,490.89
	TOTAL NUMBER OF MORTAGES	CERTIFICATE ACCOUNT ACTIVITY (@ PCRATE)	CERTIFICATE BALANCE OUTSTANDING
BALANCES FROM LAST FISCAL MONTH-END:	1843		$675,943,034.95
PRINCIPAL POOL COLLECTION(S):
Scheduled Principal Collection Due Current Month		$145,970.11
Unscheduled Principal Collection/Reversals		$340,634.86
Liquidations-in-full	28	$12,581,425.83
Net principal Distributed		$13,068,030.80	-$13,068,030.80

CAPITAL LOSS (PRINCIPAL WRITTEN OFF):			$0.00

BALANCE CURRENT FISCAL MONTH-END:	1815		$662,875,004.15

SCHEDULED INTEREST AT MORTGAGE RATE:		$3,047,684.33

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:		$225,314.50

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:		$15,890,400.63

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
MASTER SERVICING
MORTGAGE PASS-THROUGH CERTIFICATES
08/2003 DISTRIBUTION REPORT
SERIES: WAMMS 03AR3 WEIGHTED AVERAGE PC RATE: 4.78964%
POOL NUMBER: 2127
ISSUE DATE: 06/26/2003
CERTIFICATE BALANCE AT ISSUE: $127,692,778.44
	TOTAL NUMBER OF MORTAGES	CERTIFICATE ACCOUNT ACTIVITY (@ PCRATE)	CERTIFICATE BALANCE OUTSTANDING
BALANCES FROM LAST FISCAL MONTH-END:	244		$125,082,194.37
PRINCIPAL POOL COLLECTION(S):
Scheduled Principal Collection Due Current Month		$25,695.87
Unscheduled Principal Collection/Reversals		$126,933.96
Liquidations-in-full	8	$4,865,552.52
Net principal Distributed		$5,018,182.35	-$5,018,182.35

CAPITAL LOSS (PRINCIPAL WRITTEN OFF):			$0.00

BALANCE CURRENT FISCAL MONTH-END:	236		$120,064,012.02

SCHEDULED INTEREST AT MORTGAGE RATE:		$540,942.49

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:		$41,694.13

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:		$5,517,430.71

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
MASTER SERVICING
MORTGAGE PASS-THROUGH CERTIFICATES
08/2003 DISTRIBUTION REPORT
SERIES: WAMMS 03AR3 WEIGHTED AVERAGE PC RATE: 5.09499%
POOL NUMBER: 2128
ISSUE DATE: 06/26/2003
CERTIFICATE BALANCE AT ISSUE: $338,991,832.94
	TOTAL NUMBER OF MORTAGES	CERTIFICATE ACCOUNT ACTIVITY (@ PCRATE)	CERTIFICATE BALANCE OUTSTANDING
BALANCES FROM LAST FISCAL MONTH-END:	677		$338,862,818.96
PRINCIPAL POOL COLLECTION(S):
Scheduled Principal Collection Due Current Month		$60,767.85
Unscheduled Principal Collection/Reversals		$25,619.30
Liquidations-in-full	10	$4,982,146.75
Net principal Distributed		$5,068,533.90	-$5,068,533.90

CAPITAL LOSS (PRINCIPAL WRITTEN OFF):			$0.00

BALANCE CURRENT FISCAL MONTH-END:	667		$333,794,285.06

SCHEDULED INTEREST AT MORTGAGE RATE:		$1,551,705.57

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:		$112,954.44

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:		$6,507,285.03

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
MASTER SERVICING
MORTGAGE PASS-THROUGH CERTIFICATES
08/2003 DISTRIBUTION REPORT
SERIES: WAMMS 03AR3 WEIGHTED AVERAGE PC RATE: 4.80967%
POOL NUMBER: 2129
ISSUE DATE: 06/26/2003
CERTIFICATE BALANCE AT ISSUE: $60,586,857.57
	TOTAL NUMBER OF MORTAGES	CERTIFICATE ACCOUNT ACTIVITY (@ PCRATE)	CERTIFICATE BALANCE OUTSTANDING
BALANCES FROM LAST FISCAL MONTH-END:	288		$60,446,877.56
PRINCIPAL POOL COLLECTION(S):
Scheduled Principal Collection Due Current Month		$16,023.39
Unscheduled Principal Collection/Reversals		$7,381.77
Liquidations-in-full	2	$427,999.82
Net principal Distributed		$451,404.98	-$451,404.98

CAPITAL LOSS (PRINCIPAL WRITTEN OFF):			$0.00

BALANCE CURRENT FISCAL MONTH-END:	286		$59,995,472.58

SCHEDULED INTEREST AT MORTGAGE RATE:		$262,423.35

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:		$20,148.87

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:		$693,679.46

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
MASTER SERVICING
MORTGAGE PASS-THROUGH CERTIFICATES
08/2003 DISTRIBUTION REPORT
SERIES: WAMMS 03AR3 WEIGHTED AVERAGE PC RATE: 5.05582%
POOL NUMBER: 2130
ISSUE DATE: 06/26/2003
CERTIFICATE BALANCE AT ISSUE: $122,333,366.95
	TOTAL NUMBER OF MORTAGES	CERTIFICATE ACCOUNT ACTIVITY (@ PCRATE)	CERTIFICATE BALANCE OUTSTANDING
BALANCES FROM LAST FISCAL MONTH-END:	560		$121,927,745.29
PRINCIPAL POOL COLLECTION(S):
Scheduled Principal Collection Due Current Month		$32,701.07
Unscheduled Principal Collection/Reversals		$175,472.22
Liquidations-in-full	4	$981,527.22
Net principal Distributed		$1,189,700.51	-$1,189,700.51

CAPITAL LOSS (PRINCIPAL WRITTEN OFF):			$0.00

BALANCE CURRENT FISCAL MONTH-END:	556		$120,738,044.78

SCHEDULED INTEREST AT MORTGAGE RATE:		$554,346.43

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:		$40,642.62

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:		$1,703,404.32

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
MASTER SERVICING
MORTGAGE PASS-THROUGH CERTIFICATES
08/2003 DISTRIBUTION REPORT
SERIES: WAMMS 03AR3 WEIGHTED AVERAGE PC RATE: 5.20097%
POOL NUMBER: 2131
ISSUE DATE: 06/26/2003
CERTIFICATE BALANCE AT ISSUE: $29,641,654.99
	TOTAL NUMBER OF MORTAGES	CERTIFICATE ACCOUNT ACTIVITY (@ PCRATE)	CERTIFICATE BALANCE OUTSTANDING
BALANCES FROM LAST FISCAL MONTH-END:	74		$29,623,398.77
PRINCIPAL POOL COLLECTION(S):
Scheduled Principal Collection Due Current Month		$10,781.93
Unscheduled Principal Collection/Reversals		$5,227.61
Liquidations-in-full	4	$1,324,199.52
Net principal Distributed		$1,340,209.06	-$1,340,209.06

CAPITAL LOSS (PRINCIPAL WRITTEN OFF):			$0.00

BALANCE CURRENT FISCAL MONTH-END:	70		$28,283,189.71

SCHEDULED INTEREST AT MORTGAGE RATE:		$138,266.49

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:		$9,874.44

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:		$1,468,601.11

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
MASTER SERVICING
MORTGAGE PASS-THROUGH CERTIFICATES
08/2003 DISTRIBUTION REPORT
SERIES: WAMMS 03AR3 WEIGHTED AVERAGE PC RATE: 5.01055%
POOL NUMBER: ALL
ISSUE DATE: 06/26/2003
CERTIFICATE BALANCE AT ISSUE: $679,246,490.89
	TOTAL NUMBER OF MORTAGES	CERTIFICATE ACCOUNT ACTIVITY (@ PCRATE)	CERTIFICATE BALANCE OUTSTANDING
BALANCES FROM LAST FISCAL MONTH-END:	1843		$675,943,034.95
PRINCIPAL POOL COLLECTION(S):
Scheduled Principal Collection Due Current Month		$145,970.11
Unscheduled Principal Collection/Reversals		$340,634.86
Liquidations-in-full	28	$12,581,425.83
Net principal Distributed		$13,068,030.80	-$13,068,030.80

CAPITAL LOSS (PRINCIPAL WRITTEN OFF):			$0.00

BALANCE CURRENT FISCAL MONTH-END:	1815		$662,875,004.15

SCHEDULED INTEREST AT MORTGAGE RATE:		$3,047,684.33

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:		$225,314.50

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:		$15,890,400.63

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
Series: WAMMS.03AR3
Distribution Date: 08/25/2003

Distribution by Group
Pool ID		Principal		Interest		Total
Group 1(2127,2128,2129,2130,2131)		$13,068,030.80		$2,822,369.83		$15,890,400.63
Pool - 2127		$5,018,182.35		$499,248.36		$5,517,430.71
Pool - 2128		$5,068,533.90		$1,438,751.13		$6,507,285.03
Pool - 2129		$451,404.98		$242,274.48		$693,679.46
Pool - 2130		$1,189,700.51		$513,703.81		$1,703,404.32
Pool - 2131		$1,340,209.06		$128,392.05		$1,468,601.11
Aggregate		$13,068,030.80		$2,822,369.83		$15,890,400.63

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(2127,2128,2129,2130,2131)	$675,943,034.95	1843	28	1815	$662,875,004.15	$145,970.11	$12,581,425.83	$340,634.86	$13,068,030.80
Pool - 2127	$125,082,194.37	244	8	236	$120,064,012.02	$25,695.87	$4,865,552.52	$126,933.96	$5,018,182.35
Pool - 2128	$338,862,818.96	677	10	667	$333,794,285.06	$60,767.85	$4,982,146.75	$25,619.30	$5,068,533.90
Pool - 2129	$60,446,877.56	288	2	286	$59,995,472.58	$16,023.39	$427,999.82	$7,381.77	$451,404.98
Pool - 2130	$121,927,745.29	560	4	556	$120,738,044.78	$32,701.07	$981,527.22	$175,472.22	$1,189,700.51
Pool - 2131	$29,623,398.77	74	4	70	$28,283,189.71	$10,781.93	$1,324,199.52	$5,227.61	$1,340,209.06
Aggregate	$675,943,034.95	1843	28	1815	$662,875,004.15	$145,970.11	$12,581,425.83	$340,634.86	$13,068,030.80

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(2127,2128,2129,2130,2131)	17	$7,369,007.18	0	$0.00	0	$0.00	0	$0.00
Pool - 2127	4	$1,888,424.77	0	$0.00	0	$0.00	0	$0.00
Pool - 2128	7	$3,745,079.64	0	$0.00	0	$0.00	0	$0.00
Pool - 2129	0	$0.00	0	$0.00	0	$0.00	0	$0.00
Pool - 2130	4	$749,022.82	0	$0.00	0	$0.00	0	$0.00
Pool - 2131	2	$986,479.95	0	$0.00	0	$0.00	0	$0.00
Aggregate	17	$7,369,007.18	0	$0.00	0	$0.00	0	$0.00

Foreclosure and REO Information by Group
Pool ID		Foreclosure Count		Sched End Balance		REO Count		Sched End Balance
Group 1(2127,2128,2129,2130,2131)		0		$0.00		0		$0.00
Pool - 2127		0		$0.00		0		$0.00
Pool - 2128		0		$0.00		0		$0.00
Pool - 2129		0		$0.00		0		$0.00
Pool - 2130		0		$0.00		0		$0.00
Pool - 2131		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(2127,2128,2129,2130,2131)			0			$0.00
Aggregate			0			$0.00

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
Series: WAMMS.03AR3
Distribution Date: 08/25/2003

INSURANCE RESERVES - Group 1(2127,2128,2129,2130,2131)
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.03AR3
Distribution Date: 08/25/2003

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 Group I, II, III,IV, V and Class M Certificates. The "Prospectus Supplement" is that certain Prospectus Supplement, dated June 24, 2003 to that certain Prospectus Supplement, dated May 20, 2003, to which certain Group I, II, III, IV, V, and Class M Certificates were offered. The Special Hazard, Bankruptcy, and Fraud coverage (collectively, "Credit Enhancements") provided by the B certificates provide coverage to the Group I, II, III,IV, V, and Class M Loans, subject to the conditions and limitations to payment specified thereunder.



The Class Principal Balances of each Class of the Class M,B1,B2,B3,B4,B5,B6 Certificatesimmediately after the principal and interest distribution on 200308 are as follows:

Class			Class Principal Balance
M			$27,497,660.32
B1			$12,560,491.82
B2			$9,505,507.21
B3			$6,789,476.65
B4			$7,129,030.45
B5			$2,376,376.80
B6			$2,037,113.77
Total			$67,895,657.03
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 MORTGAGE SECURITIES CORP.
Series: WAMMS.03AR3
Distribution Date: 08/25/2003

Aggregate ARM Information by Group
Pool ID	Netwac	Margin
Group 1(2127,2128,2129,2130,2131)	5.01055%	1.89663%
Pool - 2127	4.78964%	1.85409%
Pool - 2128	5.09499%	1.88338%
Pool - 2129	4.80967%	1.86187%
Pool - 2130	5.05582%	1.88663%
Pool - 2131	5.20097%	2.35000%
Aggregate	5.01055%	1.89699%

MSC MORTGAGE PASS THROUGH CERTIFICATES SERIES 2003-AR3 8-K