MASTR Asset Backed Securities Trust 2004-FRE1
Mortgage Pass Through Certificates, Series 2004-FRE1

STATEMENT TO CERTIFICATEHOLDERS

Distribution Date:

09/27/04

		Original	Beginning				Allocated	Ending
		Certificate	Certificate	Principal	Interest	Total	Realized	Certificate
Class	Cusip	Face Value	Balance	Distribution	Distribution(1)	Distribution	Losses	Balance
A-1	57643LDR4	$276,076,000.00	$265,869,022.10	$10,253,854.89	$476,459.44	$10,730,314.33	$0.00	$255,615,167.21
A-2	57643LDS2	$122,267,000.00	$117,778,925.61	$5,171,070.07	$211,069.65	$5,382,139.72	$0.00	$112,607,855.54
A-IO	57643LDT0	$509,064,639.20	$494,369,586.91	N/A	$401,057.33	$401,057.33	$0.00	$478,944,661.95
M-1	57643LDU7	$19,854,000.00	$19,854,000.00	$0.00	$39,401.92	$39,401.92	$0.00	$19,854,000.00
M-2	57643LDV5	$13,999,000.00	$13,999,000.00	$0.00	$28,423.80	$28,423.80	$0.00	$13,999,000.00
M-3	57643LDW3	$11,454,000.00	$11,454,000.00	$0.00	$23,991.36	$23,991.36	$0.00	$11,454,000.00
M-4	57643LDX1	$10,181,000.00	$10,181,000.00	$0.00	$25,337.96	$25,337.96	$0.00	$10,181,000.00
M-5	57643LDY9	$8,909,000.00	$8,909,000.00	$0.00	$22,988.93	$22,988.93	$0.00	$8,909,000.00
M-6	57643LDZ6	$8,909,000.00	$8,909,000.00	$0.00	$24,622.25	$24,622.25	$0.00	$8,909,000.00
M-7	57643LEA0	$7,636,000.00	$7,636,000.00	$0.00	$23,903.86	$23,903.86	$0.00	$7,636,000.00
M-8	57643LEB8	$7,636,000.00	$7,636,000.00	$0.00	$24,953.81	$24,953.81	$0.00	$7,636,000.00
M-9	57643LEC6	$6,363,000.00	$6,363,000.00	$0.00	$29,834.52	$29,834.52	$0.00	$6,363,000.00
M-10	57643LED4	$5,091,000.00	$5,091,000.00	$0.00	$23,870.43	$23,870.43	$0.00	$5,091,000.00
CE	NA	$10,689,539.20	$10,689,539.20	$0.00	$1,360,200.62	$1,360,200.62	$0.00	$10,689,539.20
P	NA	$100.00	$100.00	$0.00	$393,301.09	$393,301.09	$0.00	$100.00
R-X	NA	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00	$0.00
Total		$509,064,639.20	$494,369,586.91	$15,424,924.96	$3,109,416.97	$18,534,341.93	$0.00	$478,944,661.95

AMOUNTS PER $1,000 UNIT						PASS THROUGH RATES
					Ending	Original	Current	Next
	Principal	Interest	Total	Realized	Certificate	Pass-Through	Pass-Through	Pass-Through
Class	Distribution	Distribution	Distribution	Losses	Balance	Interest Rate	Interest Rate	Interest Rate*
A-1	37.14142080	1.72582709	38.86724790	0.00000000	925.88695580	1.81000%	1.95500%	2.18000%
A-2	42.29326041	1.72630105	44.01956145	0.00000000	920.99957912	1.81000%	1.95500%	2.18000%
A-IO	N/A	0.78783184	0.78783184	0.00000000	940.83270585	1.03000%	0.88500%	0.66000%
M-1	0.00000000	1.98458346	1.98458346	0.00000000	1000.00000000	2.02000%	2.16500%	2.39000%
M-2	0.00000000	2.03041646	2.03041646	0.00000000	1000.00000000	2.07000%	2.21500%	2.44000%
M-3	0.00000000	2.09458355	2.09458355	0.00000000	1000.00000000	2.14000%	2.28500%	2.51000%
M-4	0.00000000	2.48874963	2.48874963	0.00000000	1000.00000000	2.57000%	2.71500%	2.94000%
M-5	0.00000000	2.58041643	2.58041643	0.00000000	1000.00000000	2.67000%	2.81500%	3.04000%
M-6	0.00000000	2.76375014	2.76375014	0.00000000	1000.00000000	2.87000%	3.01500%	3.24000%
M-7	0.00000000	3.13041645	3.13041645	0.00000000	1000.00000000	3.27000%	3.41500%	3.64000%
M-8	0.00000000	3.26791645	3.26791645	0.00000000	1000.00000000	3.42000%	3.56500%	3.79000%
M-9	0.00000000	4.68875059	4.68875059	0.00000000	1000.00000000	4.97000%	5.11500%	5.34000%
M-10	0.00000000	4.68875074	4.68875074	0.00000000	1000.00000000	4.97000%	5.11500%	5.34000%
CE	0.00000000	127.24595462	127.24595462	0.00000000	1000.00000000	3.91252%	3.30166%
P	0.00000000	3933010.9000	3933010.9000	0.00000000	1000.00000000
R-X	0.00000000	0.0000000	0.0000000	0.00000000	0.00000000
								* Estimated

(1) - The Class P Certificates do not accrue interest. Amounts appearing as Interest Distributions represent payments of Prepayment Charges.

	Please contact the Bondholder relations Department of U.S. Bank National Association at
	(800) 934-6802 with any questions regarding this statement or your distribution.

U.S. BANK NATIONAL ASSOCIATION

Page 1

MASTR Asset Backed Securities Trust 2004-FRE1
Mortgage Pass Through Certificates, Series 2004-FRE1

STATEMENT TO CERTIFICATEHOLDERS

Distribution Date:

09/27/04

Section 4.02 (i) - PREPAYMENT CHARGES
	For Allocation of Principal, SEE PAGE 1
	Prepayment Charges allocated to Class P	393,301.09
	Servicer Prepayment Charge Payment Amounts allocated to Class P	$0.00

Section 4.02 (ii) and (xv) - INTEREST

		Monthly		Remaining	Reduction from the Allocation of:
	Interest	Interest	Interest	Unpaid		Prepayment	Relief Act
	Distribution	Distributable	Shortfall	Interest	Realized	Interest	Interest
Class	Amount	Amount	Amount	Amount	Losses	Shortfalls	Shortfalls
A-1	$476,459.44	$476,459.44	$0.00	$0.00	$0.00	$0.00	$0.00
A-2	$211,069.65	$211,069.65	$0.00	$0.00	$0.00	$0.00	$0.00
A-IO	$401,057.33	$401,057.33	$0.00	$0.00	$0.00	$0.00	$0.00
M-1	$39,401.92	$39,401.92	$0.00	$0.00	$0.00	$0.00	$0.00
M-2	$28,423.80	$28,423.80	$0.00	$0.00	$0.00	$0.00	$0.00
M-3	$23,991.36	$23,991.36	$0.00	$0.00	$0.00	$0.00	$0.00
M-4	$25,337.96	$25,337.96	$0.00	$0.00	$0.00	$0.00	$0.00
M-5	$22,988.93	$22,988.93	$0.00	$0.00	$0.00	$0.00	$0.00
M-6	$24,622.25	$24,622.25	$0.00	$0.00	$0.00	$0.00	$0.00
M-7	$23,903.86	$23,903.86	$0.00	$0.00	$0.00	$0.00	$0.00
M-8	$24,953.81	$24,953.81	$0.00	$0.00	$0.00	$0.00	$0.00
M-9	$29,834.52	$29,834.52	$0.00	$0.00	$0.00	$0.00	$0.00
M-10	$23,870.43	$23,870.43	$0.00	$0.00	$0.00	$0.00	$0.00
CE	$1,360,200.62	1,360,200.62	$0.00	$0.00	$0.00	$0.00	$0.00
P	$393,301.09	N/A	N/A	N/A	$0.00	$0.00	$0.00
Total	$3,109,416.97	$2,716,115.88	$0.00	$0.00	$0.00	$0.00	$0.00

Section 4.02 (iii), (xii) - FEES
	Servicing Fee (and any additional Servicer compensation)	$205,951.23
	Trustee Fee	$9,681.40
	Credit Risk Manager Fee	$6,179.62
	Extraordinary Trust Fund Expenses	$0.00

Section 4.02 (iv) - ADVANCES
		Aggregate Advances for the Collection Period					$118,456.68

Section 4.02 (v) - POOL
	Stated Principal Balance of Mortgage Loans and any REO Properties	$478,944,661.95
	Number of Mortgage Loans and any REO Properties	2,691

Section 4.02 (vi) - LOANS
	Number of Mortgage Loans	2,691
	Stated Principal Balance of Mortgage Loans	$478,944,661.95
	Weighted Average Remaining Term to Maturity	346
	Weighted Average Mortgage Interest Rate	7.1343%

Section 4.02 (vii) - DELINQUENCIES

			Stated Principal	Stated Principal
	Number	Number as %	Balance	Balance as %
30-59 days delinquent	75	2.78707%	$10,944,194.41	2.28506%
60-89 days delinquent	32	1.18915%	$4,736,477.59	0.98894%
90 or more days delinquent	18	0.66890%	$2,883,345.91	0.60202%
Foreclosures	0	0.00000%	$0.00	0.00000%
Bankruptcies	0	0.00000%	$0.00	0.00000%

Section 4.02 (viii) - REO
	Number of REO Loans	0
	Number of REO Loans as %	0.00000%
	Stated Principal Balance of REO Properties	$0.00
	Stated Principal Balance of REO Properties as %	0.00000%

Page 2

MASTR Asset Backed Securities Trust 2004-FRE1
Mortgage Pass Through Certificates, Series 2004-FRE1

STATEMENT TO CERTIFICATEHOLDERS

Distribution Date:

09/27/04

Section 4.02 (x), (xxiii) - AVAILABLE FUNDS
	Principal:
	Scheduled Principal	$360,322.50
	Principal Prepayments (includes curtailments)	$15,064,602.46
	Liquidation Proceeds	$0.00
	Total Principal	$15,424,924.96
	Net Interest (net of servicing & trustee fee)	$2,716,115.88
	Available Funds (total principal plus net interest)	$18,141,040.84

Section 4.02 (xi) - LOSSES
	Current Realized Losses	$0.00
	Aggregate Realized Losses	$0.00
	Subsequent Recoveries	$0.00
	Aggregate Subsequent Recoveries	$0.00

Section 4.02 (xiii), (xiv) - BALANCES
		For Certificate Balances and Loss Allocations, SEE PAGE 1

Section 4.02 (xviii)
	Overcollateralization Target Amount	$10,689,539.20
	Overcollateralized Amount	$10,689,639.20
	Overcollateralization Deficiency	$0.00
	Overcollateralization Release Amount	$0.00
	Credit Enhancement Percentage	23.118%

Section 4.02 (xx)
	Aggregate Realized Losses	$0.00
	Aggregate Balance of Liquidated Loans	$0.00
	Aggregate Loss Severity Percentage	0.00000%

Section 4.02 (xxi)
	Stepdown Date Occurrence	NO
	Trigger Event Occurrence	NO

Section 4.02 (xxiii) - NET WAC RATE CARRYOVER AMOUNTS

	Net WAC Rate	Cap Contract	Amounts
Class	Carryover Amount	Payment Amount	Unpaid
A-1	$0.00	$0.00	$0.00
A-2	$0.00	$0.00	$0.00
M-1	$0.00	$0.00	$0.00
M-2	$0.00	$0.00	$0.00
M-3	$0.00	$0.00	$0.00
M-4	$0.00	$0.00	$0.00
M-5	$0.00	$0.00	$0.00
M-6	$0.00	$0.00	$0.00
M-7	$0.00	$0.00	$0.00
M-8	$0.00	$0.00	$0.00
M-9	$0.00	$0.00	$0.00
M-10	$0.00	$0.00	$0.00

Section 4.02 (xxiv) - PAYMENTS MADE UNDER CAP CONTRACTS
	A-1 Cap Contract	0.00
	A-2 Cap Contract	0.00
	Mezzanine Contract	0.00

Page 3

MASTR Asset Backed Securities Trust 2004-FRE1
Mortgage Pass Through Certificates, Series 2004-FRE1

STATEMENT TO CERTIFICATEHOLDERS

Distribution Date:

09/27/04

Section 4.02 (xiv) - ENDING BALANCE FACTORS

			Class	Factor
			A-1	0.925887
			A-2	0.921000
			M-1	1.000000
			M-2	1.000000
			M-3	1.000000
			M-4	1.000000
			M-5	1.000000
			M-6	1.000000
			M-7	1.000000
			M-8	1.000000
			M-9	1.000000
			M-10	1.000000
			CE	1.000000
			P	1.000000

Page 4

MASTR ASSET BACKED SECURITIES TRUST 2004-FRE1 8-K