WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
Series: WAMMS.03AR3
Distribution Date: 12/27/2004

Class	Cusip	Orig Prin Bal	Begin Prin Bal	Int Rate Accrued	Int Rate Paid	Int Dist	Prin Dist	Int Shortfall	PPIS	Uncomp Int Shortfall	Prin Loss	Deferred Interest	Int Reimbursed	Unsched Int	Prin Reimbursed	Subsequent Recoveries	Total Dist	Ending Class Bal
IA	939336G23	$114,923,400.00	$35,476,464.28	3.5470464229%	3.5470464229%	$104,863.89	$3,337,574.14	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$3,442,438.03	$32,138,890.14
IIA1	939336G31	$23,850,000.00	$10,028,897.66	5.0519643475%	5.0519643475%	$42,221.36	$765,325.36	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$807,546.73	$9,263,572.30
IIA2	939336G49	$281,242,600.00	$118,262,191.19	3.9999643475%	3.9999643475%	$394,203.79	$9,024,825.80	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$9,419,029.59	$109,237,365.39
IIIA	939336G56	$54,528,100.00	$22,783,896.72	4.7963896586%	4.7963896586%	$91,067.04	$2,007,456.78	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$2,098,523.82	$20,776,439.94
IVA	939336G64	$110,100,000.00	$57,569,770.64	5.0370864758%	5.0370864758%	$241,653.26	$1,955,544.98	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$2,197,198.24	$55,614,225.66
VA	939336G72	$26,677,400.00	$15,445,687.67	5.1596059527%	5.1596059527%	$66,411.39	$10,347.93	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$76,759.32	$15,435,339.74
IX	939336G80	$114,923,400.00	$35,476,464.28	1.2280000000%	1.2280000000%	$36,304.25	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$36,304.25	$32,138,890.14
IIX	939336G98	$281,242,600.00	$118,262,191.19	1.0520000000%	1.0520000000%	$103,676.52	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$103,676.52	$109,237,365.39
M	939336H22	$27,509,500.00	$27,232,192.48	4.9790053853%	4.9790053853%	$112,991.03	$877,961.68	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$990,952.70	$26,354,230.80
B1	939336H30	$12,565,900.00	$12,439,230.34	4.9790053853%	4.9790053853%	$51,612.50	$401,038.86	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$452,651.36	$12,038,191.48
B2	939336H48	$9,509,600.00	$9,413,739.17	4.9790053853%	4.9790053853%	$39,059.22	$303,497.50	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$342,556.71	$9,110,241.67
B3	939336H55	$6,792,400.00	$6,723,929.69	4.9790053853%	4.9790053853%	$27,898.74	$216,778.45	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$244,677.19	$6,507,151.24
B4	939336H71	$7,132,100.00	$7,060,205.38	4.9790053853%	4.9790053853%	$29,294.00	$227,619.93	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$256,913.93	$6,832,585.45
B5	939336H89	$2,377,400.00	$2,353,434.79	4.9790053853%	4.9790053853%	$9,764.80	$75,874.37	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$85,639.18	$2,277,560.42
B6	939336H97	$2,037,990.89	$2,017,447.04	4.9790053853%	4.9790053853%	$8,370.73	$65,042.18	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$73,412.91	$1,952,404.86
R	939336H63	$100.00	$0.00	0.0000000000%	0.0000000000%	$0.18	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.18	$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	$0.00	$0.00	$0.00
Total		$679,246,490.89	$326,807,087.05			$1,359,392.68	$19,268,887.97	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$20,628,280.65	$307,538,199.08

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
Series: WAMMS.03AR3
Distribution Date: 12/27/2004

Class	Orig Face	Beg Bal	Prin Loss	Prin Reimbursed	Subsequent Recoveries	Deferred Interest	Total Prin	End Cert Pct	End Cert Bal
IA	$114,923,400.00	$35,476,464.28	$0.00	$0.00	$0.00	$0.00	$3,337,574.14	0.2796548844	$32,138,890.14
IIA1	$23,850,000.00	$10,028,897.66	$0.00	$0.00	$0.00	$0.00	$765,325.36	0.3884097400	$9,263,572.30
IIA2	$281,242,600.00	$118,262,191.19	$0.00	$0.00	$0.00	$0.00	$9,024,825.80	0.3884097409	$109,237,365.39
IIIA	$54,528,100.00	$22,783,896.72	$0.00	$0.00	$0.00	$0.00	$2,007,456.78	0.3810226276	$20,776,439.94
IVA	$110,100,000.00	$57,569,770.64	$0.00	$0.00	$0.00	$0.00	$1,955,544.98	0.5051246654	$55,614,225.66
VA	$26,677,400.00	$15,445,687.67	$0.00	$0.00	$0.00	$0.00	$10,347.93	0.5785923568	$15,435,339.74
IX	$114,923,400.00	$35,476,464.28	$0.00	$0.00	$0.00	$0.00	$0.00	0.2796548844	$32,138,890.14
IIX	$281,242,600.00	$118,262,191.19	$0.00	$0.00	$0.00	$0.00	$0.00	0.3884097409	$109,237,365.39
M	$27,509,500.00	$27,232,192.48	$0.00	$0.00	$0.00	$0.00	$877,961.68	0.9580047184	$26,354,230.80
B1	$12,565,900.00	$12,439,230.34	$0.00	$0.00	$0.00	$0.00	$401,038.86	0.9580047175	$12,038,191.48
B2	$9,509,600.00	$9,413,739.17	$0.00	$0.00	$0.00	$0.00	$303,497.50	0.9580047184	$9,110,241.67
B3	$6,792,400.00	$6,723,929.69	$0.00	$0.00	$0.00	$0.00	$216,778.45	0.9580047170	$6,507,151.24
B4	$7,132,100.00	$7,060,205.38	$0.00	$0.00	$0.00	$0.00	$227,619.93	0.9580047181	$6,832,585.45
B5	$2,377,400.00	$2,353,434.79	$0.00	$0.00	$0.00	$0.00	$75,874.37	0.9580047194	$2,277,560.42
B6	$2,037,990.89	$2,017,447.04	$0.00	$0.00	$0.00	$0.00	$65,042.18	0.9580047043	$1,952,404.86
R	$100.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	0.0000000000	$0.00
R_SYN	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	0.0000000000	$0.00
Total	$679,246,490.89	$326,807,087.05	$0.00	$0.00	$0.00	$0.00	$19,268,887.97	0.4527637657	$307,538,199.08

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
Series: WAMMS.03AR3
Distribution Date: 12/27/2004
PER $1000 DENOMINATION
Class	Orig Face	Beg Bal	Prin Loss	Prin Reimbursed	Subsequent Recoveries	Deferred Interest	Total Prin	End Cert Pct	End Cert Bal
IA	$114,923,400.00	308.69661253	0.00000000	0.00000000	0.00000000	0.00000000	29.04172814	0.2796548844	279.65488438
IIA1	$23,850,000.00	420.49885367	0.00000000	0.00000000	0.00000000	0.00000000	32.08911363	0.3884097400	388.40974004
IIA2	$281,242,600.00	420.49885469	0.00000000	0.00000000	0.00000000	0.00000000	32.08911381	0.3884097409	388.40974088
IIIA	$54,528,100.00	417.83771523	0.00000000	0.00000000	0.00000000	0.00000000	36.81508763	0.3810226276	381.02262760
IVA	$110,100,000.00	522.88620018	0.00000000	0.00000000	0.00000000	0.00000000	17.76153479	0.5051246654	505.12466540
VA	$26,677,400.00	578.98024808	0.00000000	0.00000000	0.00000000	0.00000000	0.38789125	0.5785923568	578.59235683
IX	$114,923,400.00	308.69661253	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.2796548844	279.65488438
IIX	$281,242,600.00	420.49885469	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.3884097409	388.40974088
M	$27,509,500.00	989.91957251	0.00000000	0.00000000	0.00000000	0.00000000	31.91485414	0.9580047184	958.00471837
B1	$12,565,900.00	989.91957122	0.00000000	0.00000000	0.00000000	0.00000000	31.91485369	0.9580047175	958.00471753
B2	$9,509,600.00	989.91957285	0.00000000	0.00000000	0.00000000	0.00000000	31.91485446	0.9580047184	958.00471839
B3	$6,792,400.00	989.91957040	0.00000000	0.00000000	0.00000000	0.00000000	31.91485337	0.9580047170	958.00471704
B4	$7,132,100.00	989.91957208	0.00000000	0.00000000	0.00000000	0.00000000	31.91485397	0.9580047181	958.00471811
B5	$2,377,400.00	989.91957180	0.00000000	0.00000000	0.00000000	0.00000000	31.91485236	0.9580047194	958.00471944
B6	$2,037,990.89	989.91955749	0.00000000	0.00000000	0.00000000	0.00000000	31.91485316	0.9580047043	958.00470433
R	$100.00	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.0000000000	0.00000000
R_SYN	$0.00	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.0000000000	0.00000000

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
Series: WAMMS.03AR3
Distribution Date: 12/27/2004

Class	Orig Face	Int Rate Accrued	Int Rate Paid	Beg Cert Prin/Not Bal	Current Int Accrued	Int Shortfall	PPIS	Uncompensated Int Shortfall	Unscheduled Int	Int Reimbursed	Total Int Dist
IA	$114,923,400.00	3.5470464229%	3.5470464229%	$35,476,464.28	$104,863.89	$0.00	$0.00	$0.00	$0.00	$0.00	$104,863.89
IIA1	$23,850,000.00	5.0519643475%	5.0519643475%	$10,028,897.66	$42,221.36	$0.00	$0.00	$0.00	$0.00	$0.00	$42,221.36
IIA2	$281,242,600.00	3.9999643475%	3.9999643475%	$118,262,191.19	$394,203.79	$0.00	$0.00	$0.00	$0.00	$0.00	$394,203.79
IIIA	$54,528,100.00	4.7963896586%	4.7963896586%	$22,783,896.72	$91,067.04	$0.00	$0.00	$0.00	$0.00	$0.00	$91,067.04
IVA	$110,100,000.00	5.0370864758%	5.0370864758%	$57,569,770.64	$241,653.26	$0.00	$0.00	$0.00	$0.00	$0.00	$241,653.26
VA	$26,677,400.00	5.1596059527%	5.1596059527%	$15,445,687.67	$66,411.39	$0.00	$0.00	$0.00	$0.00	$0.00	$66,411.39
IX	$114,923,400.00	1.2280000000%	1.2280000000%	$35,476,464.28	$36,304.25	$0.00	$0.00	$0.00	$0.00	$0.00	$36,304.25
IIX	$281,242,600.00	1.0520000000%	1.0520000000%	$118,262,191.19	$103,676.52	$0.00	$0.00	$0.00	$0.00	$0.00	$103,676.52
M	$27,509,500.00	4.9790053853%	4.9790053853%	$27,232,192.48	$112,991.03	$0.00	$0.00	$0.00	$0.00	$0.00	$112,991.03
B1	$12,565,900.00	4.9790053853%	4.9790053853%	$12,439,230.34	$51,612.50	$0.00	$0.00	$0.00	$0.00	$0.00	$51,612.50
B2	$9,509,600.00	4.9790053853%	4.9790053853%	$9,413,739.17	$39,059.22	$0.00	$0.00	$0.00	$0.00	$0.00	$39,059.22
B3	$6,792,400.00	4.9790053853%	4.9790053853%	$6,723,929.69	$27,898.74	$0.00	$0.00	$0.00	$0.00	$0.00	$27,898.74
B4	$7,132,100.00	4.9790053853%	4.9790053853%	$7,060,205.38	$29,294.00	$0.00	$0.00	$0.00	$0.00	$0.00	$29,294.00
B5	$2,377,400.00	4.9790053853%	4.9790053853%	$2,353,434.79	$9,764.80	$0.00	$0.00	$0.00	$0.00	$0.00	$9,764.80
B6	$2,037,990.89	4.9790053853%	4.9790053853%	$2,017,447.04	$8,370.73	$0.00	$0.00	$0.00	$0.00	$0.00	$8,370.73
R	$100.00	0.0000000000%	0.0000000000%	$0.00	$0.18	$0.00	$0.00	$0.00	$0.00	$0.00	$0.18
R_SYN	$0.00	0.0000000000%	0.0000000000%	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00
Total	$679,246,490.89			$326,807,087.05	$1,359,392.68	$0.00	$0.00	$0.00	$0.00	$0.00	$1,359,392.68

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
Series: WAMMS.03AR3
Distribution Date: 12/27/2004
PER $1000 DENOMINATION
Class	Orig Face	Int Rate Accrued	Int Rate Paid	Beg Cert Prin/Not Bal	Curent Int Accrued	Int Shortfall	PPIS	Uncompensated Int Shortfall	Unscheduled Int	Int Reimbursed	Total Int Dist
IA	$114,923,400.00	3.5470464229%	3.5470464229%	308.69661253	0.91246770	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.91246770
IIA1	$23,850,000.00	5.0519643475%	5.0519643475%	420.49885367	1.77028763	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	1.77028763
IIA2	$281,242,600.00	3.9999643475%	3.9999643475%	420.49885469	1.40165035	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	1.40165035
IIIA	$54,528,100.00	4.7963896586%	4.7963896586%	417.83771523	1.67009377	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	1.67009377
IVA	$110,100,000.00	5.0370864758%	5.0370864758%	522.88620018	2.19485250	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	2.19485250
VA	$26,677,400.00	5.1596059527%	5.1596059527%	578.98024808	2.48942513	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	2.48942513
IX	$114,923,400.00	1.2280000000%	1.2280000000%	308.69661253	0.31589955	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.31589955
IIX	$281,242,600.00	1.0520000000%	1.0520000000%	420.49885469	0.36863733	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.36863733
M	$27,509,500.00	4.9790053853%	4.9790053853%	989.91957251	4.10734583	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	4.10734583
B1	$12,565,900.00	4.9790053853%	4.9790053853%	989.91957122	4.10734607	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	4.10734607
B2	$9,509,600.00	4.9790053853%	4.9790053853%	989.91957285	4.10734626	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	4.10734626
B3	$6,792,400.00	4.9790053853%	4.9790053853%	989.91957040	4.10734645	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	4.10734645
B4	$7,132,100.00	4.9790053853%	4.9790053853%	989.91957208	4.10734566	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	4.10734566
B5	$2,377,400.00	4.9790053853%	4.9790053853%	989.91957180	4.10734416	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	4.10734416
B6	$2,037,990.89	4.9790053853%	4.9790053853%	989.91955749	4.10734417	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	4.10734417
R	$100.00	0.0000000000%	0.0000000000%	0.00000000	1.80000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	1.80000000
R_SYN	$0.00	0.0000000000%	0.0000000000%	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
MASTER SERVICING
MORTGAGE PASS-THROUGH CERTIFICATES
12/2004 DISTRIBUTION REPORT
SERIES: WAMMS 03AR3
WEIGHTED AVERAGE PC RATE: 4.77505%
WEIGHTED AVERAGE MATURITY: 338.84943
WEIGHTED AVERAGE LOAN AGE: 19.59950
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:	98		$48,120,970.41
PRINCIPAL POOL COLLECTION(S):
Scheduled Principal Collection Due Current Month		$10,387.47
Unscheduled Principal Collection/Reversals		$737.66
Liquidations-in-full	6	$3,832,843.99
Subsequent Recoveries		$0.00
Net principal Distributed		$3,843,969.12	-$3,843,969.12

CAPITAL LOSS (PRINCIPAL WRITTEN OFF):			$0.00

BALANCE CURRENT FISCAL MONTH-END:	92		$44,277,001.29

SCHEDULED INTEREST AT MORTGAGE RATE:		$207,523.56

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
Interest Uncollected on Prepayment		$0.00
Uncompensated Uncollected Interest		$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
Recoveries Carried Forward		$0.00
Net Other Distributions		$0.00

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
MASTER SERVICING
MORTGAGE PASS-THROUGH CERTIFICATES
12/2004 DISTRIBUTION REPORT
	TOTAL NUMBER OF MORTAGES	CERTIFICATE ACCOUNT ACTIVITY (@ PCRATE)	CERTIFICATE BALANCE OUTSTANDING
SCHEDULED SERVICING FEE EXPENSES:		$16,040.34

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:		$4,035,452.34

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
MASTER SERVICING
MORTGAGE PASS-THROUGH CERTIFICATES
12/2004 DISTRIBUTION REPORT
SERIES: WAMMS 03AR3
WEIGHTED AVERAGE PC RATE: 5.05196%
WEIGHTED AVERAGE MATURITY: 340.32920
WEIGHTED AVERAGE LOAN AGE: 19.56610
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:	323		$161,888,419.70
PRINCIPAL POOL COLLECTION(S):
Scheduled Principal Collection Due Current Month		$893,814.53
Unscheduled Principal Collection/Reversals		$18,521.01
Liquidations-in-full	23	$10,114,817.96
Subsequent Recoveries		$0.00
Net principal Distributed		$11,027,153.50	-$11,027,153.50

CAPITAL LOSS (PRINCIPAL WRITTEN OFF):			$0.00

BALANCE CURRENT FISCAL MONTH-END:	300		$150,861,266.20

SCHEDULED INTEREST AT MORTGAGE RATE:		$735,508.23

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
Interest Uncollected on Prepayment		$0.00
Uncompensated Uncollected Interest		$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
Recoveries Carried Forward		$0.00
Net Other Distributions		$0.00

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
MASTER SERVICING
MORTGAGE PASS-THROUGH CERTIFICATES
12/2004 DISTRIBUTION REPORT
	TOTAL NUMBER OF MORTAGES	CERTIFICATE ACCOUNT ACTIVITY (@ PCRATE)	CERTIFICATE BALANCE OUTSTANDING
SCHEDULED SERVICING FEE EXPENSES:		$53,962.77

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:		$11,708,698.96

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
MASTER SERVICING
MORTGAGE PASS-THROUGH CERTIFICATES
12/2004 DISTRIBUTION REPORT
SERIES: WAMMS 03AR3
WEIGHTED AVERAGE PC RATE: 4.79639%
WEIGHTED AVERAGE MATURITY: 339.15119
WEIGHTED AVERAGE LOAN AGE: 19.56253
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:	147		$28,787,699.03
PRINCIPAL POOL COLLECTION(S):
Scheduled Principal Collection Due Current Month		$9,720.75
Unscheduled Principal Collection/Reversals		$1,155.03
Liquidations-in-full	12	$2,231,414.44
Subsequent Recoveries		$0.00
Net principal Distributed		$2,242,290.22	-$2,242,290.22

CAPITAL LOSS (PRINCIPAL WRITTEN OFF):			$0.00

BALANCE CURRENT FISCAL MONTH-END:	135		$26,545,408.81

SCHEDULED INTEREST AT MORTGAGE RATE:		$124,660.07

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
Interest Uncollected on Prepayment		$0.00
Uncompensated Uncollected Interest		$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
Recoveries Carried Forward		$0.00
Net Other Distributions		$0.00

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
MASTER SERVICING
MORTGAGE PASS-THROUGH CERTIFICATES
12/2004 DISTRIBUTION REPORT
	TOTAL NUMBER OF MORTAGES	CERTIFICATE ACCOUNT ACTIVITY (@ PCRATE)	CERTIFICATE BALANCE OUTSTANDING
SCHEDULED SERVICING FEE EXPENSES:		$9,595.80

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:		$2,357,354.49

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
MASTER SERVICING
MORTGAGE PASS-THROUGH CERTIFICATES
12/2004 DISTRIBUTION REPORT
SERIES: WAMMS 03AR3
WEIGHTED AVERAGE PC RATE: 5.03709%
WEIGHTED AVERAGE MATURITY: 339.87333
WEIGHTED AVERAGE LOAN AGE: 19.59108
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:	340		$69,681,311.74
PRINCIPAL POOL COLLECTION(S):
Scheduled Principal Collection Due Current Month		$19,795.43
Unscheduled Principal Collection/Reversals		$10,825.88
Liquidations-in-full	10	$2,112,933.20
Subsequent Recoveries		$0.00
Net principal Distributed		$2,143,554.51	-$2,143,554.51

CAPITAL LOSS (PRINCIPAL WRITTEN OFF):			$0.00

BALANCE CURRENT FISCAL MONTH-END:	330		$67,537,757.23

SCHEDULED INTEREST AT MORTGAGE RATE:		$315,719.49

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
Interest Uncollected on Prepayment		$0.00
Uncompensated Uncollected Interest		$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
Recoveries Carried Forward		$0.00
Net Other Distributions		$0.00

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
MASTER SERVICING
MORTGAGE PASS-THROUGH CERTIFICATES
12/2004 DISTRIBUTION REPORT
	TOTAL NUMBER OF MORTAGES	CERTIFICATE ACCOUNT ACTIVITY (@ PCRATE)	CERTIFICATE BALANCE OUTSTANDING
SCHEDULED SERVICING FEE EXPENSES:		$23,227.11

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:		$2,436,046.89

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
MASTER SERVICING
MORTGAGE PASS-THROUGH CERTIFICATES
12/2004 DISTRIBUTION REPORT
SERIES: WAMMS 03AR3
WEIGHTED AVERAGE PC RATE: 5.15961%
WEIGHTED AVERAGE MATURITY: 338.97941
WEIGHTED AVERAGE LOAN AGE: 20.46097
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:	48		$18,328,686.17
PRINCIPAL POOL COLLECTION(S):
Scheduled Principal Collection Due Current Month		$8,076.12
Unscheduled Principal Collection/Reversals		$3,844.50
Liquidations-in-full	0	$0.00
Subsequent Recoveries		$0.00
Net principal Distributed		$11,920.62	-$11,920.62

CAPITAL LOSS (PRINCIPAL WRITTEN OFF):			$0.00

BALANCE CURRENT FISCAL MONTH-END:	48		$18,316,765.55

SCHEDULED INTEREST AT MORTGAGE RATE:		$84,916.89

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
Interest Uncollected on Prepayment		$0.00
Uncompensated Uncollected Interest		$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
Recoveries Carried Forward		$0.00
Net Other Distributions		$0.00

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
MASTER SERVICING
MORTGAGE PASS-THROUGH CERTIFICATES
12/2004 DISTRIBUTION REPORT
	TOTAL NUMBER OF MORTAGES	CERTIFICATE ACCOUNT ACTIVITY (@ PCRATE)	CERTIFICATE BALANCE OUTSTANDING
SCHEDULED SERVICING FEE EXPENSES:		$6,109.54

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:		$90,727.97

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
MASTER SERVICING
MORTGAGE PASS-THROUGH CERTIFICATES
12/2004 DISTRIBUTION REPORT
SERIES: WAMMS 03AR3
WEIGHTED AVERAGE PC RATE: 4.99154%
WEIGHTED AVERAGE MATURITY: 339.83397
WEIGHTED AVERAGE LOAN AGE: 19.62938
POOL NUMBER: Group 1
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:	956		$326,807,087.05
PRINCIPAL POOL COLLECTION(S):
Scheduled Principal Collection Due Current Month		$941,794.30
Unscheduled Principal Collection/Reversals		$35,084.08
Liquidations-in-full	51	$18,292,009.59
Subsequent Recoveries		$0.00
Net principal Distributed		$19,268,887.97	-$19,268,887.97

CAPITAL LOSS (PRINCIPAL WRITTEN OFF):			$0.00

BALANCE CURRENT FISCAL MONTH-END:	905		$307,538,199.08

SCHEDULED INTEREST AT MORTGAGE RATE:		$1,468,328.24

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
Interest Uncollected on Prepayment		$0.00
Uncompensated Uncollected Interest		$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
Recoveries Carried Forward		$0.00
Net Other Distributions		$0.00

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
MASTER SERVICING
MORTGAGE PASS-THROUGH CERTIFICATES
12/2004 DISTRIBUTION REPORT
	TOTAL NUMBER OF MORTAGES	CERTIFICATE ACCOUNT ACTIVITY (@ PCRATE)	CERTIFICATE BALANCE OUTSTANDING
SCHEDULED SERVICING FEE EXPENSES:		$108,935.56

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:		$20,628,280.65

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
MASTER SERVICING
MORTGAGE PASS-THROUGH CERTIFICATES
12/2004 DISTRIBUTION REPORT
SERIES: WAMMS 03AR3
WEIGHTED AVERAGE PC RATE: 4.99154%
WEIGHTED AVERAGE MATURITY: 339.83397
WEIGHTED AVERAGE LOAN AGE: 19.62938
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:	956		$326,807,087.05
PRINCIPAL POOL COLLECTION(S):
Scheduled Principal Collection Due Current Month		$941,794.30
Unscheduled Principal Collection/Reversals		$35,084.08
Liquidations-in-full	51	$18,292,009.59
Subsequent Recoveries		$0.00
Net principal Distributed		$19,268,887.97	-$19,268,887.97

CAPITAL LOSS (PRINCIPAL WRITTEN OFF):			$0.00

BALANCE CURRENT FISCAL MONTH-END:	905		$307,538,199.08

SCHEDULED INTEREST AT MORTGAGE RATE:		$1,468,328.24

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
Interest Uncollected on Prepayment		$0.00
Uncompensated Uncollected Interest		$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
Recoveries Carried Forward		$0.00
Net Other Distributions		$0.00

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
MASTER SERVICING
MORTGAGE PASS-THROUGH CERTIFICATES
12/2004 DISTRIBUTION REPORT
	TOTAL NUMBER OF MORTAGES	CERTIFICATE ACCOUNT ACTIVITY (@ PCRATE)	CERTIFICATE BALANCE OUTSTANDING
SCHEDULED SERVICING FEE EXPENSES:		$108,935.56

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:		$20,628,280.65

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
Series: WAMMS.03AR3
Distribution Date: 12/27/2004

Distribution by Group
Pool ID		Principal		Interest		Total
Pool - 2127		$3,843,969.12		$191,483.22		$4,035,452.34
Pool - 2128		$11,027,153.50		$681,545.46		$11,708,698.96
Pool - 2129		$2,242,290.22		$115,064.27		$2,357,354.49
Pool - 2130		$2,143,554.51		$292,492.38		$2,436,046.89
Pool - 2131		$11,920.62		$78,807.35		$90,727.97
Group 1		$19,268,887.97		$1,359,392.68		$20,628,280.65
Aggregate		$19,268,887.97		$1,359,392.68		$20,628,280.65

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
Pool - 2127	$48,120,970.41	98	6	92	$44,277,001.29	$10,387.47	$3,832,843.99	$737.66	$3,843,969.12
Pool - 2128	$161,888,419.70	323	23	300	$150,861,266.20	$893,814.53	$10,114,817.96	$18,521.01	$11,027,153.50
Pool - 2129	$28,787,699.03	147	12	135	$26,545,408.81	$9,720.75	$2,231,414.44	$1,155.03	$2,242,290.22
Pool - 2130	$69,681,311.74	340	10	330	$67,537,757.23	$19,795.43	$2,112,933.20	$10,825.88	$2,143,554.51
Pool - 2131	$18,328,686.17	48	0	48	$18,316,765.55	$8,076.12	$0.00	$3,844.50	$11,920.62
Group 1	$326,807,087.05	956	51	905	$307,538,199.08	$941,794.30	$18,292,009.59	$35,084.08	$19,268,887.97
Aggregate	$326,807,087.05	956	51	905	$307,538,199.08	$941,794.30	$18,292,009.59	$35,084.08	$19,268,887.97

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
Pool - 2127	3	$1,303,737.67	0	$0.00	0	$0.00	0	$0.00
Pool - 2128	0	$0.00	0	$0.00	0	$0.00	0	$0.00
Pool - 2129	1	$215,200.00	0	$0.00	0	$0.00	0	$0.00
Pool - 2130	8	$1,465,458.21	0	$0.00	1	$176,000.00	0	$0.00
Pool - 2131	0	$0.00	0	$0.00	0	$0.00	0	$0.00
Group 1	12	$2,984,395.88	0	$0.00	1	$176,000.00	0	$0.00
Aggregate	12	$2,984,395.88	0	$0.00	1	$176,000.00	0	$0.00

Foreclosure and REO Information by Group
Pool ID		Foreclosure Count		Sched End Balance		REO Count		Sched End Balance
Pool - 2127		0		$0.00		0		$0.00
Pool - 2128		1		$524,914.40		0		$0.00
Pool - 2129		1		$270,859.95		0		$0.00
Pool - 2130		2		$435,103.32		0		$0.00
Pool - 2131		0		$0.00		0		$0.00
Group 1		4		$1,230,877.67		0		$0.00
Aggregate		4		$1,230,877.67		0		$0.00

Aggregate Loss Amounts by Group
Pool ID			Count			Loss Amount
Pool - 2127			0			$0.00
Pool - 2128			0			$0.00
Pool - 2129			0			$0.00
Pool - 2130			0			$0.00
Pool - 2131			0			$0.00
Group 1			0			$0.00
Aggregate			0			$0.00

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
Series: WAMMS.03AR3
Distribution Date: 12/27/2004

INSURANCE RESERVES - Group 1
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	$6,792,464.00	$0.00	$0.00	$0.00	$6,792,464.00
Bankruptcy Bond
Single-Units	$150,000.00	$0.00	$0.00	$0.00	$150,000.00
Multi-Units	$0.00	$0.00	$0.00	$0.00	$0.00
Mortgage Repurchase	$20,377,394.00	$0.00	$0.00	$0.00	$20,377,394.00

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	$6,792,464.00	$0.00	$0.00	$0.00	$6,792,464.00
Bankruptcy Bond
Single-Units	$150,000.00	$0.00	$0.00	$0.00	$150,000.00
Multi-Units	$0.00	$0.00	$0.00	$0.00	$0.00
Mortgage Repurchase	$20,377,394.00	$0.00	$0.00	$0.00	$20,377,394.00

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.
Series: WAMMS.03AR3
Distribution Date: 12/27/2004

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 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 200412 are as follows:

Class			Class Principal Balance
M			$26,354,230.80
B1			$12,038,191.48
B2			$9,110,241.67
B3			$6,507,151.24
B4			$6,832,585.45
B5			$2,277,560.42
B6			$1,952,404.86
Total			$65,072,365.92
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 $6,792,464.00, $150,000.00, $20,377,394.00 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."

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