
                                       UNITED STATES
                           SECURITIES AND EXCHANGE COMMISSION
                                 Washington, D.C.  20549


                                        FORM 8-K


                     Current Report Pursuant To Section 13 or 15(d) of
                            the Securities Exchange Act of 1934

           Date of Report (Date of earliest event reported):  September 27, 2004
                          (Date of earliest event reported)

            Indymac MBS Inc (as Depositor under the Pooling and Servicing
                Agreement, dated as June 1, 2004, providing for the
                issuance of IndyMAc INDX Mortgage Loan Trust 2004-AR3
                Mortgage Pass-Through Certificates, Series 2004-AR3)
                 (Exact name of registrant as specified in charter)


                                     DELAWARE
                     (State or Other Jurisdiction of Incorporation)

               333-116470-01                         95-4791925
          (Commission File Number)        (I.R.S. Employer Identification No.)


          155 NORTH LAKE AVENUE
          PASADENA, CALIFORNIA                         91101
          (Address of principal executive offices)     (Zip Code)



          Registrant's Telephone Number, Including Area Code:  (800) 669-2300

       (Former name or former address, if changed since last report.)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any
of the following provisions (see General Instruction A.2. below):

[  ] Written communications pursuant to Rule 425 under the Securities Act
(17 CFR 230.425)

[  ] Soliciting material pursuant to Rule 14a-12(b) under the Exchange Act
(17 CFR 240.14a-12(b))

[  ] Pre-commencement communications pursuant to Rule 14d-2(b) under the
Exchange Act (17 CFR 240.14d-2(b))

[  ] Pre-commencement communications pursuant to Rule 13e-4(c) under the
Exchange Act (17 CFR 240.13e-4(c))


     Item 8.01  Other Events

     Attached hereto is a copy of the Monthly Remittance Statements to the
     Certificateholders which was derived from the monthly information
     submitted by the Master Servicer of the Trust to the Trustee.


     Item 9.01 Financial Statements and Exhibits

     (c) Exhibits:

     Exhibit No. Description

     99.1 Monthly Remittance Statement to the Certificateholders dated as of
     September 27, 2004.

                                    Signatures

               Pursuant to the requirements of the Securities Exchange Act of
          1934, the Registrant has duly caused this report to be signed on its
          behalf by the undersigned, hereunto duly authorized.


                                  Deutsche Bank National Trust Company,
                                  in its capacity as Trustee under the
                                  Pooling and Servicing Agreement on
                                  behalf of Indymac MBS Inc, Registrant


          Date:  Sep 27, 2004               By:  /s/  Katherine M. Wannenmacher
                                            Katherine M. Wannenmacher
                                            Vice President


                                   EXHIBIT INDEX

          DOCUMENT

          99.1 Monthly Remittance Statement to the Certificateholders
          dated as of September 27, 2004.


	IndyMac INDX Mortgage Loan Trust 2004-AR3
	Collateralized Asset-Backed Bonds


	September 27, 2004 Distribution


	Contents



			TABLE OF CONTENTS

								Page

			1.	Contents				1
			2.	Certificate Payment Report				2
			3.	Collection Account Report				4
			4.	Credit Enhancement Report				7
			5.	Collateral Report				8
			6.	Delinquency Report				11
			7.	REO Report				12
			8.	Prepayment Report				13
			9.	Prepayment Detail Report				16
			10.	Realized Loss Report				18
			11.	Realized Loss Detail Report				21
			12.	Triggers, Adj. Rate Cert. and Miscellaneous Report				22
			13.	Other Related Information				23
			14.	Additional Certificate Report				24



				Total Number of Pages				24



			CONTACTS

				Administrator: Brent Hoyler
				Direct Phone Number: (714)247-6322
				Address: Deutsche Bank
				1761 E. St. Andrew Place, Santa Ana, CA 92705

				Web Site: https://www.corporatetrust.db.com/invr
				Factor Information: (800) 735-7777
				Main Phone Number: (714) 247-6000



ISSUANCE INFORMATION

	Seller:		IndyMac Bank					Cut-Off Date: June 1, 2004
	Certificate Insurer(s):							Closing Date: June 29, 2004
								First Payment Date: July 26, 2004
	Servicer(s):		IndyMac Bank Master Servicer


								Distribution Date: September 27, 2004
	Underwriter(s):		Greenwich Capital Markets Underwriter					Record Date: August 31, 2004







						Page 1 of 24					© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR3
	Collateralized Asset-Backed Bonds

	Certificate Payment Report for September 27, 2004 Distribution


	Distribution in Dollars - Current Period
					Prior						Current
	Class	Original			Principal			Total	Realized	Deferred	Principal
Class	Type	Face Value			Balance	Interest	Principal	Distribution	Losses	Interest	Balance
					(1)	(2)	(3)	(4)=(2)+(3)	(5)	(6)	(7)=(1)-(3)-(5)+(6)

A-1		560,470,000.00			541,665,695.91	891,491.46	12,496,642.54	13,388,134.00	-	-	529,169,053.37
A-X-1		-			-	344,894.71	-	344,894.71	-	-	-
A-X-2		-			105,589.17	547,262.24	-	547,262.24	-	74,908.98	180,498.15
A-R		100.00			-	-	-	-	-	-	-
B-1		17,120,000.00			17,110,420.91	30,157.12	4,100.67	34,257.79	-	-	17,106,320.24
B-2		7,810,000.00			7,805,630.10	17,660.24	1,870.69	19,530.93	-	-	7,803,759.41
B-3		4,800,000.00			4,797,314.27	11,453.59	1,149.72	12,603.31	-	-	4,796,164.55
B-4		4,800,000.00			4,797,314.27	11,453.59	1,149.72	12,603.31	-	-	4,796,164.55
B-5		3,600,000.00			3,597,985.71	8,590.19	862.29	9,452.48	-	-	3,597,123.41
B-6		2,448,913.91			2,447,543.70	5,843.50	586.57	6,430.07	-	-	2,446,957.13
P		100.00			100.00	115,186.52	-	115,186.52	-	-	100.00


Total		601,049,113.91			582,327,594.04	1,983,993.16	12,506,362.22	14,490,355.38	-	74,908.98	569,896,140.81


	Interest Accrual Detail				Current Period Factor Information per $1,000 of Original Face
						Orig. Principal	Prior				Current
	Period	Period				(with Notional)	Principal			Total	Principal
Class	Starting	Ending		Method	Cusip	Balance	Balance	Interest	Principal	Distribution	Balance
							(1)	(2)	(3)	(4)=(2)+(3)	(5)

A-1				A-30/360	45660NL78	560,470,000.00	966.449044	1.590614	22.296720	23.887334	944.152325
A-X-1				A-30/360	45660NL86	560,470,000.00	923.050417	0.615367	-	0.615367	886.679428
A-X-2				A-30/360	45660NL94	601,049,013.91	969.027600	0.910512	-	0.910512	948.469302
A-R				A-30/360	45660NM28	100.00	-	-	-	-	-
B-1				A-30/360	45660NM36	17,120,000.00	999.440474	1.761514	0.239525	2.001039	999.200948
B-2				A-30/360	45660NM44	7,810,000.00	999.440474	2.261234	0.239525	2.500760	999.200948
B-3				A-30/360	45660NM51	4,800,000.00	999.440474	2.386165	0.239525	2.625690	999.200948
B-4				A-30/360	45660NR72	4,800,000.00	999.440474	2.386165	0.239525	2.625690	999.200948
B-5				A-30/360	45660NR08	3,600,000.00	999.440474	2.386164	0.239525	2.625689	999.200948
B-6				A-30/360	45660NR98	2,448,913.91	999.440483	2.386160	0.239524	2.625683	999.200959
P				F-30/360		100.00	1,000.000000	1,151,865.200000	-	1,151,865.200000	1,000.000000


							Page 2 of 24				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR3
	Collateralized Asset-Backed Bonds

	Certificate Payment Report for September 27, 2004 Distribution


	Distribution in Dollars - to Date
											Current
	Original				Unscheduled	Scheduled	Total	Total	Realized	Deferred	Principal
Class	Face Value		Interest		Principal	Principal	Principal	Distribution	Losses	Interest	Balance
	(1)		(2)		(3)	(4)	(5)=(3)+(4)	(6)=(2)+(5)	(7)	(8)	(9)=(1)-(5)-(7)+(8)

A-1	560,470,000.00		2,435,488.85		-	31,300,946.63	31,300,946.63	33,736,435.48	-	-	529,169,053.37
A-X-1	-		1,077,541.83		-	-	-	1,077,541.83	-	-	-
A-X-2	-		1,886,088.99		-	-	-	1,886,088.99	-	180,498.15	180,498.15
A-R	100.00		0.32		-	100.00	100.00	100.32	-	-	-
B-1	17,120,000.00		81,466.30		-	13,679.76	13,679.76	95,146.06	-	-	17,106,320.24
B-2	7,810,000.00		48,485.44		-	6,240.59	6,240.59	54,726.03	-	-	7,803,759.41
B-3	4,800,000.00		31,538.48		-	3,835.45	3,835.45	35,373.93	-	-	4,796,164.55
B-4	4,800,000.00		31,538.48		-	3,835.45	3,835.45	35,373.93	-	-	4,796,164.55
B-5	3,600,000.00		23,653.86		-	2,876.59	2,876.59	26,530.45	-	-	3,597,123.41
B-6	2,448,913.91		16,090.62		-	1,956.78	1,956.78	18,047.40	-	-	2,446,957.13
P	100.00		290,235.85		-	-	-	290,235.85	-	-	100.00


Total	601,049,113.91		5,922,129.02		-	31,333,471.25	31,333,471.25	37,255,600.28	-	180,498.15	569,896,140.81


	Interest Detail
	Pass-	Prior Principal				Non-	Prior	Unscheduled		Paid or	Current
	Through	(with Notional)			Accrued	Supported	Unpaid	Interest	Optimal	Deferred	Unpaid
Class	Rate	Balance			Interest	Interest SF	Interest	Adjustments	Interest	Interest	Interest
					(1)	(2)	(3)	(4)	(5)=(1)-(2)+(3)+(4)	(6)	(7)=(5)-(6)

A-1	1.97500%	541,665,695.91			891,491.46	-	-	-	891,491.46	891,491.46	-
A-X-1	0.80000%	517,342,067.00			344,894.71	-	0.00	-	344,894.71	344,894.71	-
A-X-2	1.28211%	582,433,083.19			622,171.22	-	0.00	-	622,171.22	622,171.22	0.00
A-R	4.00541%	-			-	-	-	-	-	-	-
B-1	2.11500%	17,110,420.91			30,157.12	-	-	-	30,157.12	30,157.12	-
B-2	2.71500%	7,805,630.10			17,660.24	-	-	-	17,660.24	17,660.24	-
B-3	2.86500%	4,797,314.27			11,453.59	-	-	-	11,453.59	11,453.59	-
B-4	2.86500%	4,797,314.27			11,453.59	-	-	-	11,453.59	11,453.59	-
B-5	2.86500%	3,597,985.71			8,590.19	-	-	-	8,590.19	8,590.19	-
B-6	2.86500%	2,447,543.70			5,843.51	-	-	-	5,843.51	5,843.50	(0.00)
P		100.00			115,186.52	-	-	-	115,186.52	115,186.52	-


Total		1,681,997,155.06			2,058,902.15	-	0.01	-	2,058,902.16	2,058,902.14	0.00


							Page 3 of 24				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR3
	Collateralized Asset-Backed Bonds

	Collection Account Report for September 27, 2004 Distribution


	Collection Account Report


SUMMARY								TOTAL

	Principal Collections							12,431,453.24
	Principal Withdrawals							0.00
	Principal Other Accounts							0.00
	TOTAL PRINCIPAL							12,431,453.24

	Interest Collections							1,986,274.44
	Interest Withdrawals							0.00
	Interest Other Accounts							115,186.52
	Interest Fees							(42,558.82)

	TOTAL INTEREST							2,058,902.14

	TOTAL AVAILABLE FUNDS TO BONDHOLDERS							14,490,355.38

	Interest Payable to Bondholders							2,058,902.14


PRINCIPAL - COLLECTIONS								TOTAL

	Scheduled Principal							139,560.30
	Curtailments							324,819.04
	Prepayments in Full							11,967,073.90
	Repurchases/Substitutions							0.00
	Liquidations							0.00
	Insurance Principal							0.00
	Other Additional Principal							0.00
	LESS: Delinquent Principal							(111,409.77)
	LESS: Realized Losses							0.00
	PLUS: Recoveries							0.00
	PLUS: Substitution Shortfall Principal							0.00
	PLUS: Principal Loan Adjustments							0.00
	PLUS: Principal Advanced							111,409.77
	TOTAL PRINCIPAL							12,431,453.24


				Page 4 of 24				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR3
	Collateralized Asset-Backed Bonds

	Collection Account Report for September 27, 2004 Distribution


	Collection Account Report


PRINCIPAL - WITHDRAWALS								TOTAL
SPACE INTENTIONALLY LEFT BLANK


PRINCIPAL - OTHER ACCOUNTS								TOTAL



	TOTAL PRINCIPAL OTHER ACCOUNTS							0.00


INTEREST - COLLECTIONS								TOTAL

	Scheduled Interest							2,128,361.97
	Repurchases/Substitutions							0.00
	Liquidations							0.00
	Insurance Interest							0.00
	Other Additional Interest							0.00
	LESS: Prepayment Interest Shortfalls							(5,382.78)
	LESS: Delinquent Interest							(1,663,746.13)
	LESS: Interest Realized Losses							0.00
	PLUS: Compensating Interest							5,382.78
	LESS: Civil Relief Act Shorfalls							0.00
	PLUS: Substiution Shortfall Interest							0.00
	PLUS: Interest Loan Adjustments							0.00
	LESS: Excess, Special Hazard, Fraud, & Bankruptcy Interest Losses							0.00
	Interest Advanced							1,521,658.60
	TOTAL INTEREST							1,986,274.44


				Page 5 of 24				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR3
	Collateralized Asset-Backed Bonds

	Collection Account Report for September 27, 2004 Distribution


	Collection Account Report


INTEREST - WITHDRAWALS								TOTAL
SPACE INTENTIONALLY LEFT BLANK


INTEREST - OTHER ACCOUNTS								TOTAL

	Prepayment Penalties							115,186.52



	TOTAL INTEREST OTHER ACCOUNTS							115,186.52


INTEREST - FEES								TOTAL

	Current Servicing Fees							39,889.82
	Trustee Fees							2,669.00
	PMI Fees							0.00

	TOTAL INTEREST FEES							42,558.82


				Page 6 of 24				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR3
	Collateralized Asset-Backed Bonds

	Credit Enhancement Report for September 27, 2004 Distribution


	Credit Enhancement Report


ACCOUNTS								TOTAL
SPACE INTENTIONALLY LEFT BLANK


INSURANCE								TOTAL
SPACE INTENTIONALLY LEFT BLANK


STRUCTURAL FEATURES								TOTAL
SPACE INTENTIONALLY LEFT BLANK


				Page 7 of 24				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR3
	Collateralized Asset-Backed Bonds

	Collateral Report for September 27, 2004 Distribution


	Collateral Report


COLLATERAL								TOTAL
	Loan Count:
	*Original*							3077
	Prior							2,987
	Prefunding							-
	Scheduled Paid Offs							-
	Full Voluntary Prepayments							(61)
	Repurchases							-
	Liquidations							-
	Current							2,926

	*Principal Balance:*
	Original							601,049,013.91
	Prior							582,327,494.02
	Prefunding							-
	Scheduled Principal							(139,560.30)
	Partial and Full Voluntary Prepayments							(12,291,892.94)
	Repurchases							-
	Liquidations							-
	Current							569,896,040.78

PREFUNDING								TOTAL
SPACE INTENTIONALLY LEFT BLANK




Current Prin Balance by Groups (in millions of dollars)					Total Current Principal Balance (in millions of dollars)


				Page 8 of 24				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR3
	Collateralized Asset-Backed Bonds

	Collateral Report for September 27, 2004 Distribution


	Collateral Report


CHARACTERISTICS								TOTAL

	Weighted Average Coupon Original							4.242594%
	Weighted Average Coupon Prior							4.292824%
	Weighted Average Coupon Current							4.385907%
	Weighted Average Months to Maturity Original							351
	Weighted Average Months to Maturity Prior							350
	Weighted Average Months to Maturity Current							349
	Weighted Avg Remaining Amortization Term Original							351
	Weighted Avg Remaining Amortization Term Prior							350
	Weighted Avg Remaining Amortization Term Current							349
	Weighted Average Seasoning Original							9.07
	Weighted Average Seasoning Prior							10.06
	Weighted Average Seasoning Current							11.03

Note: Original information refers to deal issue.




WAC by Groups					Total WAC


WARAT by Groups					Total WARAT


Note: Dates correspond to distribution dates.
				Page 9 of 24				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR3
	Collateralized Asset-Backed Bonds

	Collateral Report for September 27, 2004 Distribution


	Collateral Report


ARM CHARACTERISTICS								TOTAL

	Weighted Average Margin Original							3.007%
	Weighted Average Margin Prior							3.006%
	Weighted Average Margin Current							3.006%
	Weighted Average Max Rate Original							9.986%
	Weighted Average Max Rate Prior							9.984%
	Weighted Average Max Rate Current							9.981%
	Weighted Average Min Rate Original							3.006%
	Weighted Average Min Rate Prior							3.006%
	Weighted Average Min Rate Current							3.006%
	Weighted Average Cap Up Original							0.000%
	Weighted Average Cap Up Prior							0.000%
	Weighted Average Cap Up Current							0.000%
	Weighted Average Cap Down Original							0.000%
	Weighted Average Cap Down Prior							0.000%
	Weighted Average Cap Down Current							0.000%

Note: Original information refers to deal issue.

SERVICING FEES / ADVANCES								TOTAL

	Current Servicing Fees							39,889.82
	Delinquent Servicing Fees							142,087.53
	TOTAL SERVICING FEES							181,977.35

	Total Servicing Fees							181,977.35
	Compensating Interest							(5,382.78)
	Delinquent Servicing Fees							(142,087.53)
	COLLECTED SERVICING FEES							34,507.04

	Total Advanced Principal For Current Payment Date							111,409.77
	Total Advanced Interest For Current Payment Date							1,521,658.60
	TOTAL ADVANCES FOR CURRENT PERIOD							1,633,068.37


ADDITIONAL COLLATERAL INFORMATION								TOTAL

	Prepayment Interest Shortfall (PPIS)							5,382.78
	Compensating Interest							(5,382.78)
	Net Prepayment Interest Shortfall (Net PPIS)							0.00

	Weighted Average Net Mortgage Rate							4.005407%


				Page 10 of 24				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR3
	Collateralized Asset-Backed Bonds

	Delinquency Report for September 27, 2004 Distribution


	Delinquency Report - Total


				<1 PAYMENT	1 PAYMENT	2 PAYMENTS	3+ PAYMENTS	TOTAL
DELINQUENT		Balance		###########	3,547,211.89	463,643.39	428,057.05	4,438,912.33
		% Balance		78.86%	0.62%	0.08%	0.08%	0.78%
		# Loans		2,271	19	3	2	24
		% # Loans		77.61%	0.65%	0.10%	0.07%	0.82%
FORECLOSURE		Balance		-	-	-	-	-
		% Balance		0.00%	0.00%	0.00%	0.00%	0.00%
		# Loans		-	-	-	-	-
		% # Loans		0.00%	0.00%	0.00%	0.00%	0.00%
BANKRUPTCY		Balance		356,306.21	121,442.72	-	-	477,748.93
		% Balance		0.06%	0.02%	0.00%	0.00%	0.08%
		# Loans		2	1	-	-	3
		% # Loans		0.07%	0.03%	0.00%	0.00%	0.10%
REO		Balance		-	-	-	-	-
		% Balance		0.00%	0.00%	0.00%	0.00%	0.00%
		# Loans		-	-	-	-	-
		% # Loans		0.00%	0.00%	0.00%	0.00%	0.00%

TOTAL		Balance		356,306.21	3,668,654.61	463,643.39	428,057.05	4,916,661.26
		% Balance		0.06%	0.64%	0.08%	0.08%	0.86%
		# Loans		2	20	3	2	27
		% # Loans		0.07%	0.68%	0.10%	0.07%	0.92%
Note: <1 Payment = 1-30days, 1 Payment = 31-60days, 2 Payments = 61-90days, 3+ Payments = 91+
								6 Months Moving Average
1 or 2 Payments Delinquent					3 or More Payments Delinquent


Total Foreclosure					Total Bankruptcy and REO


Note: Dates correspond to distribution dates.
				Page 11 of 24				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR3
	Collateralized Asset-Backed Bonds

	REO Report for September 27, 2004 Distribution


	REO Report - Mortgage Loans that Become REO During Current Distribution


SUMMARY				LOAN GROUP

Total Loan Count = 0				Loan Group 1 = Group 1; REO Book Value = 000.00
Total Original Principal Balance = 000.00
Total Current Balance = 000.00
REO Book Value = 000.00

REO Book Value reported corresponds to total REO loans, including loans that become REO during current distribution.

Loan Number		Original	Stated		Current	State &
&		Principal	Principal	Paid to	Note	LTV at	Original	Origination
Loan Group		Balance	Balance	Date	Rate	Origination	Term	Date
SPACE INTENTIONALLY LEFT BLANK


				Page 12 of 24				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR3
	Collateralized Asset-Backed Bonds

	Prepayment Report for September 27, 2004 Distribution


	Prepayment Report - Voluntary Prepayments


VOLUNTARY PREPAYMENTS								TOTAL

	*Current*
	Number of Paid in Full Loans							61
	Number of Repurchased Loans							-
	Total Number of Loans Prepaid in Full							61

	Paid in Full Balance							11,967,073.90
	Repurchased Loans Balance							-
	Curtailments Amount							324,819.04
	Total Prepayment Amount							12,291,892.94

	*Cumulative*
	Number of Paid in Full Loans							151
	Number of Repurchased Loans							-
	Total Number of Loans Prepaid in Full							151

	Paid in Full Balance							29,816,628.66
	Repurchased Loans Balance							-
	Curtailments Amount							862,542.82
	Total Prepayment Amount							30,679,171.48

SPACE INTENTIONALLY LEFT BLANK


Total Prepayments by Groups (in thousands of dollars)					Total Prepayments (in thousands of dollars)


				Page 13 of 24				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR3
	Collateralized Asset-Backed Bonds

	Prepayment Report for September 27, 2004 Distribution


	Prepayment Report - Voluntary Prepayments


VOLUNTARY PREPAYMENT RATES								TOTAL

	SMM							2.11%
	3 Months Avg SMM							1.73%
	12 Months Avg SMM
	Avg SMM Since Cut-off							1.73%

	CPR							22.59%
	3 Months Avg CPR							18.92%
	12 Months Avg CPR
	Avg CPR Since Cut-off							18.92%

	PSA							1023.85%
	3 Months Avg PSA Approximation							940.92%
	12 Months Avg PSA Approximation
	Avg PSA Since Cut-off Approximation							940.92%







CPR by Groups					Total CPR


PSA by Groups					Total PSA


				Page 14 of 24				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR3
	Collateralized Asset-Backed Bonds

	Prepayment Report for September 27, 2004 Distribution


	Prepayment Report - Voluntary Prepayments




CPR Avg since Cut-Off by Groups					Total CPR Avg since Cut-Off


PSA Avg since Cut-Off by Groups					Total PSA Avg since Cut-Off


PREPAYMENT CALCULATION METHODOLOGY
Single Monthly Mortality (SMM): (Voluntary partial and full prepayments + Repurchases)/(Beg Principal Balance - Sched Principal)
Conditional Prepayment Rate (CPR): 1-((1-SMM)^12)
PSA Standard Prepayment Model: CPR/(0.02*min(30,WAS))
Average SMM over period between nth month and mth month (AvgSMMn,m): [(1-SMMn) * (1-SMMn+1) .......(1-SMMm)]^(1/months in period n,m)
Average CPR over period between the nth month and mth month (AvgCPRn,m): 1-((1-AvgSMMn,m)^12)
Average PSA Approximation over period between the nth month and mth month: AvgCPRn,m/(0.002*Avg WASn,m))
Average WASn,m: (min(30,WASn)+min(30,WASn+1)+.......+min(30,WASm)/(number of months in the period n,m)
Weighted Average Seasoning (WAS)

Note: Prepayment rates are calculated since deal issue date and include partial and full voluntary prepayments and repurchases.
Dates correspond to distribution dates.

				Page 15 of 24				© COPYRIGHT 2004 Deutsche Bank


	IndyMac INDX Mortgage Loan Trust 2004-AR3
	Collateralized Asset-Backed Bonds

	Prepayment Detail Report for September 27, 2004 Distribution


	Prepayment Detail Report - Loans Prepaid in Full During Current Distribution


SUMMARY						LOAN GROUP

Total Loan Count = 61						Loan Group 1 = Group 1
Total Original Principal Balance = 12,091,170.00
Total Prepayment Amount = 11,967,073.90


Loan Number			Original			Current	State &	Type Prepayment
&		Loan	Principal	Prepayment	Prepayment	Note	LTV at	&	Origination
Loan Group		Status	Balance	Amount	Date	Rate	Origination	Original Term	Date

1039884 1			142,000.00	134,021.25	Aug-18-04	3.931%	WA - 67.62%	Paid Off - 360	Jul-01-01
1197472 1			203,000.00	191,876.85	Sep-07-04	3.631%	NY - 73.55%	Paid Off - 360	Oct-01-01
1698708 1			169,600.00	164,212.10	Sep-01-04	3.981%	MN - 80.00%	Paid Off - 360	Sep-01-02
1731369 1			200,000.00	191,757.35	Aug-23-04	4.381%	CA - 62.02%	Paid Off - 360	Sep-01-02
1749565 1			287,200.00	276,404.60	Sep-02-04	3.581%	CA - 80.00%	Paid Off - 360	Sep-01-02
1988303 1			155,000.00	143,975.08	Sep-07-04	3.881%	MI - 55.36%	Paid Off - 360	Jan-01-03
2082581 1			160,000.00	157,401.39	Aug-23-04	3.781%	FL - 80.00%	Paid Off - 360	Feb-01-03
2162517 1			125,000.00	122,395.09	Aug-17-04	3.981%	CA - 52.08%	Paid Off - 360	Mar-01-03
2238534 1			155,700.00	153,802.31	Sep-02-04	4.181%	MI - 56.62%	Paid Off - 360	Apr-01-03
2299731 1			223,000.00	221,118.92	Sep-01-04	4.281%	CA - 64.64%	Paid Off - 360	Apr-01-03
2467918 1			252,500.00	249,621.94	Aug-30-04	3.981%	CA - 76.52%	Paid Off - 360	Jun-01-03
2546776 1			230,000.00	224,956.99	Aug-31-04	4.381%	CA - 51.11%	Paid Off - 360	Sep-01-03
2601188 1			183,000.00	179,982.48	Aug-27-04	4.181%	CA - 59.03%	Paid Off - 360	Aug-01-03
2606135 1			148,000.00	146,663.09	Sep-14-04	4.081%	NV - 80.00%	Paid Off - 360	Aug-01-03
2643740 1			142,000.00	139,456.55	Aug-30-04	4.181%	CA - 39.23%	Paid Off - 360	Sep-01-03
2722621 1			285,000.00	284,406.00	Sep-02-04	4.581%	CA - 69.85%	Paid Off - 360	Sep-01-03
2800221 1			234,500.00	233,276.20	Sep-03-04	4.181%	CA - 72.15%	Paid Off - 360	Sep-01-03
2800619 1			263,000.00	262,340.69	Aug-20-04	4.481%	CA - 69.21%	Paid Off - 360	Nov-01-03
2801417 1			251,250.00	249,633.80	Sep-13-04	4.931%	CA - 75.00%	Paid Off - 360	Oct-01-03
2847512 1			296,000.00	295,111.59	Aug-20-04	4.406%	CO - 75.90%	Paid Off - 360	Dec-01-03
2858602 1			235,000.00	231,548.99	Sep-10-04	3.931%	CA - 77.05%	Paid Off - 360	Nov-01-03
2907705 1			231,200.00	229,088.62	Aug-17-04	4.081%	TX - 78.11%	Paid Off - 360	Jan-01-04
2941746 1			259,000.00	259,139.72	Sep-02-04	4.931%	CA - 69.07%	Paid Off - 360	Dec-01-03
2961693 1			300,000.00	296,684.33	Sep-10-04	4.281%	CA - 80.00%	Paid Off - 360	Dec-01-03
2976783 1			155,970.00	155,363.97	Sep-07-04	4.481%	TX - 69.32%	Paid Off - 360	Nov-01-03
2985731 1			160,000.00	160,194.39	Aug-20-04	5.031%	CA - 80.00%	Paid Off - 360	Dec-01-03
2997994 1			258,750.00	257,316.61	Aug-19-04	4.081%	CA - 75.00%	Paid Off - 360	Nov-01-03
3001829 1			169,600.00	169,949.02	Aug-26-04	5.081%	CA - 80.00%	Paid Off - 360	Nov-01-03
3025759 1			58,000.00	57,779.96	Sep-03-04	4.481%	MI - 54.72%	Paid Off - 360	Dec-01-03
3044748 1			320,000.00	316,268.21	Sep-03-04	3.981%	CA - 69.56%	Paid Off - 360	Jan-01-04
3048261 1			150,000.00	148,080.95	Aug-16-04	4.481%	CA - 58.82%	Paid Off - 360	Dec-01-03
3060614 1			268,000.00	268,290.33	Aug-27-04	5.081%	CA - 80.00%	Paid Off - 360	Dec-01-03
3076902 1			176,000.00	176,035.49	Aug-25-04	4.881%	CA - 74.89%	Paid Off - 360	Dec-01-03
3091422 1			94,000.00	93,970.80	Aug-26-04	4.481%	CA - 71.21%	Paid Off - 360	Jan-01-04
3106369 1			153,600.00	152,187.77	Aug-18-04	5.081%	CA - 80.00%	Paid Off - 360	Dec-01-03
3106909 1			234,000.00	233,577.24	Sep-10-04	4.681%	CT - 75.48%	Paid Off - 360	Jan-01-04
3119366 1			197,000.00	195,628.11	Sep-14-04	4.381%	KY - 92.06%	Paid Off - 360	Dec-01-03
3120211 1			131,250.00	131,090.41	Aug-26-04	4.881%	CA - 70.19%	Paid Off - 360	Jan-01-04
3124629 1			116,000.00	115,632.36	Aug-24-04	4.381%	CA - 58.00%	Paid Off - 360	Dec-01-03
3125785 1			108,000.00	107,179.66	Sep-15-04	5.081%	CA - 77.70%	Paid Off - 360	Jan-01-04
3138472 1			120,000.00	119,292.22	Aug-30-04	4.481%	FL - 75.00%	Paid Off - 360	Jan-01-04
3148218 1			228,000.00	227,566.09	Sep-13-04	4.581%	FL - 80.00%	Paid Off - 360	Feb-01-04
3166583 1			195,000.00	192,454.07	Aug-20-04	4.481%	CA - 56.52%	Paid Off - 360	Jan-01-04
3169702 1			129,000.00	128,683.11	Sep-09-04	4.481%	CA - 23.45%	Paid Off - 360	Jan-01-04

					Page 16 of 24				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR3
	Collateralized Asset-Backed Bonds

	Prepayment Detail Report for September 27, 2004 Distribution


	Prepayment Detail Report - Loans Prepaid in Full During Current Distribution



Loan Number			Original			Current	State &
&		Loan	Principal	Prepayment	Prepayment	Note	LTV at	Original	Origination
Loan Group		Status	Balance	Amount	Date	Rate	Origination	Term	Date

3177766 1			304,000.00	301,825.04	Sep-15-04	3.681%	CA - 80.00%	Paid Off - 360	Jan-01-04
3178621 1			302,000.00	302,593.42	Aug-16-04	5.231%	CA - 74.94%	Paid Off - 360	Jan-01-04
3179898 1			200,800.00	199,668.46	Sep-03-04	4.881%	CA - 80.00%	Paid Off - 360	Jan-01-04
3198634 1			121,500.00	121,012.63	Aug-16-04	4.681%	CA - 79.93%	Paid Off - 360	Jan-01-04
3204637 1			215,000.00	214,923.91	Aug-23-04	4.531%	CA - 45.74%	Paid Off - 360	Feb-01-04
3214346 1			292,500.00	289,596.94	Sep-02-04	3.981%	CA - 72.04%	Paid Off - 360	Feb-01-04
3216626 1			268,000.00	267,557.14	Sep-01-04	4.981%	CA - 80.00%	Paid Off - 360	Feb-01-04
3220118 1			140,000.00	139,722.09	Aug-24-04	4.581%	IL - 57.14%	Paid Off - 360	Feb-01-04
3235762 1			201,500.00	199,434.64	Aug-26-04	4.481%	CA - 65.00%	Paid Off - 360	Jan-01-04
3245132 1			198,500.00	194,565.67	Aug-19-04	4.781%	CA - 92.33%	Paid Off - 360	Feb-01-04
3289225 1			135,000.00	134,918.22	Sep-10-04	4.481%	FL - 64.29%	Paid Off - 360	Feb-01-04
3344898 1			293,000.00	293,339.44	Sep-08-04	4.831%	CA - 76.70%	Paid Off - 360	Feb-01-04
3424025 1			153,500.00	151,938.43	Sep-03-04	4.381%	WA - 93.03%	Paid Off - 360	Apr-01-04
3471582 1			85,000.00	84,886.78	Sep-02-04	4.431%	NV - 57.82%	Paid Off - 360	Apr-01-04
3472966 1			153,000.00	152,821.74	Sep-08-04	4.481%	FL - 78.06%	Paid Off - 360	Apr-01-04
3481119 1			258,750.00	258,238.94	Sep-01-04	4.481%	CA - 74.57%	Paid Off - 360	Apr-01-04
4041285 1			216,000.00	214,613.71	Aug-25-04	4.481%	CA - 70.82%	Paid Off - 360	Jun-01-03


					Page 17 of 24				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR3
	Collateralized Asset-Backed Bonds

	Realized Loss Report for September 27, 2004 Distribution


	Realized Loss Report - Collateral


COLLATERAL REALIZED LOSSES								TOTAL

	*Current*
	Number of Loans Liquidated							-
	Collateral Realized Loss/(Gain) Amount							-
	Net Liquidation Proceeds							-

	*Cumulative*
	Number of Loans Liquidated							-
	Collateral Realized Loss/(Gain) Amount							-
	Net Liquidation Proceeds							-

	Note: Collateral Realized Loss Amount may include adjustments to loans liquidated in prior periods.


	Current Realized Losses							0.00
	Supplemental Losses (Recoveries)							0.00
	Current Net Realized Losses (Recoveries)							0.00

	Prior Cumulative Realized Loss							0.00
	Current Net Realized Loss (Recoveries)							0.00
	Current Cumulative Realized Loss							0.00

	Current Special Hazard Loss Coverage Amount							5,823,274.94
	Current Fraud Loss Coverage Amount							18,031,464.00
	Current Bankruptcy Loss Coverage Amount							150,000.00

	Class B-1 Write Down Amount							0.00
	Class B-2 Write Down Amount							0.00
	Class B-3 Write Down Amount							0.00
	Class B-4 Write Down Amount							0.00
	Class B-5 Write Down Amount							0.00
	Class B-6 Write Down Amount							0.00


							3 Months Moving Average


Collateral Loss Severity Approximation by Groups					Collateral Loss Severity Approximation


				Page 18 of 24				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR3
	Collateralized Asset-Backed Bonds

	Realized Loss Report for September 27, 2004 Distribution


	Realized Loss Report - Collateral


DEFAULT SPEEDS								TOTAL

	MDR							0.00%
	3 Months Avg MDR							0.00%
	12 Months Avg MDR
	Avg MDR Since Cut-off							0.00%

	CDR							0.00%
	3 Months Avg CDR							0.00%
	12 Months Avg CDR
	Avg CDR Since Cut-off							0.00%

	SDA							0.00%
	3 Months Avg SDA Approximation							0.00%
	12 Months Avg SDA Approximation
	Avg SDA Since Cut-off Approximation							0.00%

	Loss Severity Approximation for Current Period
	3 Months Avg Loss Severity Approximation
	12 Months Avg Loss Severity Approximation
	Avg Loss Severity Approximation Since Cut-off



CDR by Groups					Total CDR


SDA by Groups					Total SDA


				Page 19 of 24				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR3
	Collateralized Asset-Backed Bonds

	Realized Loss Report for September 27, 2004 Distribution


	Realized Loss Report - Collateral




CDR Avg since Cut-Off by Groups					Total CDR Avg since Cut-Off


SDA Avg since Cut-Off by Groups					Total SDA Avg since Cut-Off


COLLATERAL REALIZED LOSS CALCULATION METHODOLOGY
Monthly Default Rate (MDR): (Beg Principal Balance of Liquidated Loans)/(Total Beg Principal Balance)
Conditional Default Rate (CDR): 1-((1-MDR)^12)
SDA Standard Default Assumption: CDR/IF(WAS<61,MIN(30,WAS)0.02,MAX(0.03,MIN(30,WAS)0.02-0.0095*(WAS-60)))
Average MDR over period between nth month and mth month (AvgMDRn,m): [(1-MDRn) * (1-MDRn+1) .......(1-MDRm)]^(1/months in period n,m)
Average CDR over period between the nth month and mth month (AvgCDRn,m): 1-((1-AvgMDRn,m)^12)
Average SDA Approximation over period between the nth month and mth month:
AvgCDRn,m/IF(Avg WASn,m<61,MIN(30,Avg WASn,m)0.02,MAX(0.03,MIN(30,Avg WASn,m)0.02-0.0095*(Avg WASn,m-60)))
Average WASn,m: (WASn + WASn+1 +.......+ WASm )/(number of months in the period n,m)
Loss Severity Approximation for current period: sum(Realized Loss Amount)/sum(Beg Principal Balance of Liquidated Loans)
Average Loss Severity Approximation over period between nth month and mth month: Avg(Loss Severityn,m)
Note: Default rates are calculated since deal issue date and include realized gains and additional realized losses and gains from prior periods.
Dates correspond to distribution dates.

				Page 20 of 24				© COPYRIGHT 2004 Deutsche Bank


	IndyMac INDX Mortgage Loan Trust 2004-AR3
	Collateralized Asset-Backed Bonds

	Realized Loss Detail Report for September 27, 2004 Distribution


	Realized Loss Detail Report - Loans Liquidated During Current Distribution

SUMMARY							LOAN GROUP
Total Loan Count Current Losses = 0
Total Loan Count Revisions = 0						Loan Group 1 = Group 1
Total Prior Principal Balance = 0.00
Total Current Realized Loss Amount = 0.00
Total Revisions Amount = 0.00
Total Realized Loss Amount = 0.00
Total Net Liquidation Proceeds = 0.00
Note: Total Realized Loss Amount may include adjustments to loans liquidated in prior periods.

Loan Number			Current	State &		Prior	Realized		Cumulative
&		Loan	Note	LTV at	Original	Principal	Loss/(Gain)	Realized	Realized
Loan Group		Status	Rate	Origination	Term	Balance	Revisions	Loss/(Gain)	Loss/(Gain)
SPACE INTENTIONALLY LEFT BLANK


					Page 21 of 24				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR3
	Collateralized Asset-Backed Bonds

	Triggers, Adj. Rate Cert. and Miscellaneous Report for September 27, 2004 Distribution


	Triggers, Adj. Rate Cert. and Miscellaneous Report


TRIGGER EVENTS								TOTAL

	Has the Optional Termination Date been reached?							No

	Have the Sr. Prepay Step Down Cond been satisfied?							Yes

	Has the Sr. Credit Supp. Depletion Date been reached?							Yes

	Has the Spec. Haz. Coverage Term Date been reached?							No

	Has the Fraud LossCoverage Term. Date been reached?							No

	Has the Bank LossCoverage Term. Date been reached?							No


ADJUSTABLE RATE CERTIFICATE INFORMATION								TOTAL
SPACE INTENTIONALLY LEFT BLANK


ADDITIONAL INFORMATION								TOTAL

	Current Senior Percentage							93.035498%
	Next Senior Percentage							0.000000%
	Current Subordinate Percentage							6.964502%
	Next Subordinate Percentage							0.000000%
	Current Senior Prepayment Percentage							0.000000%
	Next Projected Senior Prepayment Percentage							0.000000%
	Current Subordinated Prepayment Percentage							0.000000%
	Next Projected Subordinated Prepayment Percentage							0.000000%


								0.000000%
								0.000000%

				Page 22 of 24				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR3
	Collateralized Asset-Backed Bonds

	Other Related Information for September 27, 2004 Distribution


	Other Related Information


ADDITIONAL INFORMATION								TOTAL


	Scheduled Principal
	1 Month Prior							139,560.30
	2 Months Prior							161,000.42
	3 Months Prior							173,240.93
	4 Months Prior							0.00
	5 Months Prior							0.00
	6 Months Prior							0.00
	7 Months Prior							0.00
	8 Months Prior							0.00
	9 Months Prior							0.00
	10 Months Prior							0.00
	11 Months Prior							0.00
	12 Months Prior							0.00

	Scheduled Principal on 60+ Day Delinquent Loans
	1 Month Prior							585.90
	2 Months Prior							5.88
	3 Months Prior							291.80
	4 Months Prior							0.00
	5 Months Prior							0.00
	6 Months Prior							0.00
	7 Months Prior							0.00
	8 Months Prior							0.00
	9 Months Prior							0.00
	10 Months Prior							0.00
	11 Months Prior							0.00
	12 Months Prior							0.00


				Page 23 of 24				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR3
	Collateralized Asset-Backed Bonds

	Additional Certificate Report for September 27, 2004 Distribution


	Additional Certificate Report


	CLASS	Net PPIS & Relief Act Shortfall Allocation	Unpaid Interest Amount Due	Unpaid Interest Paid	Remaining Unpaid Interest Amount	Carryover Amount Due	Carryover Amount Paid

		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	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	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	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	0.00	0.00
		0.00	0.00	0.00	(0.00)	0.00
		0.00	0.00	0.00	0.00	0.00


				Page 24 of 24				© COPYRIGHT 2004 Deutsche Bank

IndyMac INDX Mortgage Loan Trust 2004-AR3 8-K