
                                       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):  May 25, 2005
                          (Date of earliest event reported)

            Indymac MBS Inc (as Depositor under the Pooling and Servicing
                Agreement, dated as February 1, 2005, providing for the
        issuance of Residential Asset Securitization Trust Series 2005-A1
                Mortgage Pass-Through Certificates, Series 2005-A)
                 (Exact name of registrant as specified in charter)


                                        DELAWARE
                     (State or Other Jurisdiction of Incorporation)

               333-119384-14                         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
     May 25, 2005.

                                    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:  Jun 02, 2005               By:  /s/  Katherine M. Wannenmacher
                                            Katherine M. Wannenmacher
                                            Vice President


                                   EXHIBIT INDEX

          DOCUMENT

          99.1 Monthly Remittance Statement to the Certificateholders
          dated as of May 25, 2005.



IndyMac Residential Asset Securitization Trust 2005-A1

Mortgage Pass-Through Certificates
Mortgage Pass-Through Certificates
2005-A1

May 25, 2005 Distribution

				External Parties						Table of Contents

													Page
				Seller									Page
				Seller						1. Certificate Payment Report					2
				IndyMac Bank						1. Certificate Payment Report					2
				IndyMac Bank						2. Collection Account Report					4
										2. Collection Account Report					4
										3. Credit Enhancement Report					6
										4. Collateral Report					7
				Certificate Insurer(s)						5. Delinquency Report					10
				Certificate Insurer(s)						5. Delinquency Report					10
										6. REO Report					11

										7. Foreclosure Report					12
										8. Prepayment Report					13
										9. Prepayment Detail Report					16
										9. Prepayment Detail Report					16
										10. Realized Loss Report					17
										11. Realized Loss Detail Report					20
				Servicer(s)						11. Realized Loss Detail Report					20
				Servicer(s)						12. Triggers and Adj. Cert. Report					21
				IndyMac Bank						12. Triggers and Adj. Cert. Report					21
				IndyMac Bank						13. Other Related Information					22
										13. Other Related Information					22


				Underwriter(s)
				Morgan Stanley
				CS First Boston


										Total Number of Pages					22
										Total Number of Pages

				Dates						Contacts

				Cut-Off Date:			February 01, 2005			Jennifer Hermansader
				Close Date:			February 25, 2005			Administrator
				First Distribution Date:			March 25, 2005			(714) 247-6258
										Jennifer.Vandyne@db.com
										Jennifer.Vandyne@db.com
										Address:
										1761 East St. Andrew Place, Santa Ana, CA 92705
				Distribution Date:			May 25, 2005
										Factor Information:			(800) 735-7777
				Record Date:			April 29, 2005			Factor Information:			(800) 735-7777
										Main Phone Number:			(714) 247-6000
										Main Phone Number:			(714) 247-6000

										https://www.tss.db.com/invr






Page 1 of 22
IndyMac Residential Asset Securitization Trust 2005-A1

Mortgage Pass-Through Certificates
Mortgage Pass-Through Certificates
2005-A1

May 25, 2005 Distribution
Certificate Payment Report
Current Period Distribution - REMIC II
					Prior												Current
	Class		Original		Principal						Total		Realized		Deferred		Principal
	Class		Original		Principal						Total		Realized		Deferred		Principal
Class	Type	Cur	Face Value		Balance		Interest		Principal		Distribution		Loss		Interest		Balance


					(1)		(2)		(3)		(4)=(2)+(3)		(5)		(6)		(7)=(1)-(3)-(5)+(6)

A-1	SR	$	328,508,000.00		316,424,619.60		1,450,279.51		6,883,644.62		8,333,924.13		0.00		0.00		309,540,974.98
A-1	SR	$	328,508,000.00		316,424,619.60		1,450,279.51		6,883,644.62		8,333,924.13		0.00		0.00		309,540,974.98
A-2	SR	$	1,844,614.00		1,844,614.00		8,454.48		0.00		8,454.48		0.00		0.00		1,844,614.00
A-3	SR	$	50,000,000.00		50,000,000.00		229,166.67		0.00		229,166.67		0.00		0.00		50,000,000.00
A-R	SR/RES	$	100.00		0.00		0.00		0.00		0.00		0.00		0.00		0.00
A-X	SR/NTL	$	0.00		0.00		141,474.69		0.00		141,474.69		0.00		0.00		0.00
B-1	SUB	$	9,000,000.00		8,973,306.54		41,127.65		7,636.55		48,764.20		0.00		0.00		8,965,669.99
B-2	SUB	$	3,600,000.00		3,589,322.61		16,451.06		3,054.62		19,505.68		0.00		0.00		3,586,267.99
B-3	SUB	$	2,000,000.00		1,994,068.12		9,139.48		1,697.01		10,836.49		0.00		0.00		1,992,371.11
B-4	SUB/NOF	$	2,000,000.00		1,994,068.12		9,139.48		1,697.01		10,836.49		0.00		0.00		1,992,371.11
B-5	SUB/NOF	$	1,400,000.00		1,395,847.68		6,397.64		1,187.91		7,585.55		0.00		0.00		1,394,659.77
B-6	SUB/NOF	$	1,000,000.93		997,034.99		4,569.74		848.49		5,418.23		0.00		0.00		996,186.50
P	NOF	$	100.00		100.00		0.00		0.00		0.00		0.00		0.00		100.00
PO	SR	$	647,285.07		574,565.63		0.00		672.18		672.18		0.00		0.00		573,893.46


Total			400,000,100.00		387,787,547.29		1,916,200.40		6,900,438.39		8,816,638.79		0.00		0.00		380,887,108.91
Total




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

									(1)		(1)		(2)		(3)		(4)=(2)+(3)	(5)
A-1	04/01/05		04/30/05		F-30/360		45660LEU9		328,508,000.00		963.217394		4.414746		20.954268		25.369014	942.263126
A-2	04/01/05		04/30/05		F-30/360		45660LEV7		1,844,614.00		1,000.000000		4.583333		0.000000		4.583333	1,000.000000
A-3	04/01/05		04/30/05		F-30/360		45660LEW5		50,000,000.00		1,000.000000		4.583333		0.000000		4.583333	1,000.000000
A-R	04/01/05		04/30/05		F-30/360		45660LEZ8		100.00		0.000000		0.000000		0.000000		0.000000	0.000000
A-X	04/01/05		04/30/05		A-30/360		45660LEY1		364,459,197.46		967.038530		0.388177		0.000000		0.388177	948.204671
B-1	04/01/05		04/30/05		F-30/360		45660LFA2		9,000,000.00		997.034060		4.569739		0.848506		5.418244	996.185554
B-2	04/01/05		04/30/05		F-30/360		45660LFB0		3,600,000.00		997.034058		4.569739		0.848506		5.418244	996.185553
B-3	04/01/05		04/30/05		F-30/360		45660LFC8		2,000,000.00		997.034060		4.569740		0.848505		5.418245	996.185555
B-4	04/01/05		04/30/05		F-30/360		45660LFE4		2,000,000.00		997.034060		4.569740		0.848505		5.418245	996.185555
B-5	04/01/05		04/30/05		F-30/360		45660LFF1		1,400,000.00		997.034057		4.569743		0.848507		5.418250	996.185550
B-6	04/01/05		04/30/05		F-30/360		45660LFG9		1,000,000.93		997.034063		4.569736		0.848489		5.418225	996.185574
P	04/01/05		04/30/05		A-30/360		45660LFD6		100.00		1,000.000000		0.000000		0.000000		0.000000	1,000.000000
PO	04/01/05		04/30/05		A-30/360		45660LEX3		647,285.07		887.654693		0.000000		1.038461		1.038461	886.616248




Page 2 of 22
IndyMac Residential Asset Securitization Trust 2005-A1

Mortgage Pass-Through Certificates
Mortgage Pass-Through Certificates
2005-A1

May 25, 2005 Distribution

Distribution to Date - REMIC II
																	Current


	Original				Unscheduled		Scheduled		Total		Total		Realized		Deferred		Principal

Class	Face Value		Interest		Principal		Principal		Principal		Distribution		Loss		Interest		Balance
	(1)		(2)		(3)		(4)		(5)=(3)+(4)		(6)=(2)+(5)		(7)		(8)		(9)=(1)-(5)-(7)+(8)
A-1	328,508,000.00		4,443,552.55		17,531,756.91		1,435,268.11		18,967,025.02		23,410,577.57		0.00		0.00		309,540,974.98
A-2	1,844,614.00		25,363.44		0.00		0.00		0.00		25,363.44		0.00		0.00		1,844,614.00
A-3	50,000,000.00		687,500.01		0.00		0.00		0.00		687,500.01		0.00		0.00		50,000,000.00
A-R	100.00		0.46		88.59		11.41		100.00		100.46		0.00		0.00		0.00
A-X	0.00		432,732.73		0.00		0.00		0.00		432,732.73		0.00		0.00		0.00
B-1	9,000,000.00		123,578.90		0.00		34,330.01		34,330.01		157,908.91		0.00		0.00		8,965,669.99
B-2	3,600,000.00		49,431.56		0.00		13,732.01		13,732.01		63,163.57		0.00		0.00		3,586,267.99
B-3	2,000,000.00		27,461.98		0.00		7,628.89		7,628.89		35,090.87		0.00		0.00		1,992,371.11
B-4	2,000,000.00		27,461.98		0.00		7,628.89		7,628.89		35,090.87		0.00		0.00		1,992,371.11
B-5	1,400,000.00		19,223.39		0.00		5,340.23		5,340.23		24,563.62		0.00		0.00		1,394,659.77
B-6	1,000,000.93		13,731.00		0.00		3,814.43		3,814.43		17,545.43		0.00		0.00		996,186.50
P	100.00		0.00		0.00		0.00		0.00		0.00		0.00		0.00		100.00
PO	647,285.07		0.00		4,645.22		68,746.39		73,391.61		73,391.61		0.00		0.00		573,893.46


Total	400,000,100.00		5,850,038.00		17,536,490.72		1,576,500.37		19,112,991.09		24,963,029.09		0.00		0.00		380,887,108.91


Interest Detail - REMIC II
	Pass		Prior Principal				Non-		Prior		Unscheduled				Paid or		Current
	Pass		Prior Principal				Non-		Prior		Unscheduled				Paid or

	Through		(with Notional)		Accrued		Supported		Unpaid		Interest		Optimal		Deferred		Unpaid

Class	Rate		Balance		Interest		Interest SF		Interest		Adjustment		Interest		Interest		Interest
					(1)		(2)		(3)		(4)		(5)=(1)-(2)+(3)+(4)		(6)		(7)=(5)-(6)
A-1	5.50000%		316,424,619.60		1,450,279.51		0.00		0.00		0.00		1,450,279.51		1,450,279.51		0.00
A-2	5.50000%		1,844,614.00		8,454.48		0.00		0.00		0.00		8,454.48		8,454.48		0.00
A-3	5.50000%		50,000,000.00		229,166.67		0.00		0.00		0.00		229,166.67		229,166.67		0.00
A-R	0.00000%		0.00		0.00		0.00		0.00		0.00		0.00		0.00		0.00
A-X	0.48169%		352,446,086.65		141,474.69		0.00		0.00		0.00		141,474.69		141,474.69		0.00
B-1	5.50000%		8,973,306.54		41,127.65		0.00		0.00		0.00		41,127.65		41,127.65		0.00
B-2	5.50000%		3,589,322.61		16,451.06		0.00		0.00		0.00		16,451.06		16,451.06		0.00
B-3	5.50000%		1,994,068.12		9,139.48		0.00		0.00		0.00		9,139.48		9,139.48		0.00
B-4	5.50000%		1,994,068.12		9,139.48		0.00		0.00		0.00		9,139.48		9,139.48		0.00
B-5	5.50000%		1,395,847.68		6,397.64		0.00		0.00		0.00		6,397.64		6,397.64		0.00
B-6	5.50000%		997,034.99		4,569.74		0.00		0.00		0.00		4,569.74		4,569.74		0.00
P	0.00000%		100.00		0.00		0.00		0.00		0.00		0.00		0.00		0.00
PO	0.00000%		574,565.63		0.00		0.00		0.00		0.00		0.00		0.00		0.00


Total			740,233,633.94		1,916,200.40		0.00		0.00		0.00		1,916,200.40		1,916,200.40		0.00



Page 3 of 22
IndyMac Residential Asset Securitization Trust 2005-A1

Mortgage Pass-Through Certificates
Mortgage Pass-Through Certificates
2005-A1

May 25, 2005 Distribution
Collection Account Report
SUMMARY
SUMMARY
														Total
Principal Collections														6,900,438.39
Principal Withrawals														0.00
Principal Other Accounts														0.00
TOTAL NET PRINCIPAL														6,900,438.39
Interest Collections														1,954,215.86
Interest Withdrawals														-0.00
Interest Other Accounts														0.00
Interest Fees														-38,015.46
TOTAL NET INTEREST														1,916,200.40
TOTAL AVAILABLE FUNDS FOR DISTRIBUTION														8,816,638.79



PRINCIPAL - COLLECTIONS
PRINCIPAL - COLLECTIONS
															Total
Scheduled Principal Received															330,097.72
Curtailments															30,099.85
Prepayments In Full															6,540,240.82
Repurchased/Substitution adjustment amount															0.00
Liquidations															0.00
Insurance Principal															0.00
Other Additional Principal															0.00
Delinquent Principal															-260,669.64
Realized Losses															-0.00
Advanced Principal															260,669.64
TOTAL PRINCIPAL COLLECTED															6,900,438.39


PRINCIPAL - WITHDRAWALS

SPACE INTENTIONALLY LEFT BLANK



PRINCIPAL - OTHER ACCOUNTS
PRINCIPAL - OTHER ACCOUNTS
														Total
TOTAL PRINCIPAL OTHER ACCOUNTS														0.00





Page 4 of 22
IndyMac Residential Asset Securitization Trust 2005-A1

Mortgage Pass-Through Certificates
Mortgage Pass-Through Certificates
2005-A1

May 25, 2005 Distribution

INTEREST - COLLECTIONS
INTEREST - COLLECTIONS
														Total
Scheduled Interest														2,032,680.66
Repurchased/Substitution Interest														0.00
Liquidation Interest														0.00
Insurance Interest														0.00
Other Additional Interest														0.00
Prepayment Interest Shortfalls														-1,403.40
Delinquent Interest														-1,575,118.49
Compensating Interest														1,403.40
Civil Relief Act Shortfalls														-0.00
Interest Advanced														1,496,653.69
TOTAL INTEREST COLLECTED														1,954,215.86


INTEREST - WITHDRAWALS
INTEREST - WITHDRAWALS
														Total
TOTAL INTEREST WITHDRAWALS														0.00



INTEREST - OTHER ACCOUNTS
INTEREST - OTHER ACCOUNTS
														Total
Prepayment Charges														0.00
Withdrawal from capitalized interest account														0.00
TOTAL INTEREST OTHER ACCOUNTS														0.00



INTEREST - FEES
INTEREST - FEES
														Total
Current Servicing Fees														22,826.01
Trustee Fees														2,423.67
TOTAL INTEREST FEES														38,015.46




Page 5 of 22
IndyMac Residential Asset Securitization Trust 2005-A1

Mortgage Pass-Through Certificates
Mortgage Pass-Through Certificates
2005-A1

May 25, 2005 Distribution
Credit Enhancement Report
ACCOUNTS

SPACE INTENTIONALLY LEFT BLANK



INSURANCE
INSURANCE
														Total
PMI														12,765.77



STRUCTURAL FEATURES

SPACE INTENTIONALLY LEFT BLANK




Page 6 of 22
IndyMac Residential Asset Securitization Trust 2005-A1

Mortgage Pass-Through Certificates
Mortgage Pass-Through Certificates
2005-A1

May 25, 2005 Distribution
Collateral Report


COLLATERAL



															Total



Loan Count:


Original														1,008
Prior														1,099
Prefunding														0
Scheduled Paid Offs														-0
Full Voluntary Prepayments														-14
Repurchases														-0
Liquidations														-0
Current														1,085
Principal Balance:


Original														350,212,312.81
Prior														387,787,447.29
Prefunding														0.00
Scheduled Principal														-330,097.72
Partial Prepayments														-30,099.85
Full Voluntary Prepayments														-6,540,240.82
Repurchases														-0.00
Liquidations														-0.00
Current														380,887,008.90





PREFUNDING
PREFUNDING
														Total
Prefunding Account Original Balance														49,787,687.19
Prefunding Account Beginning Balance														0.00
Subsequent Loans Added to the Pool														0.00
Prefund Release to Certificate Holders														0.00
Prefunding Account Ending Balance														0.00





Page 7 of 22
IndyMac Residential Asset Securitization Trust 2005-A1

Mortgage Pass-Through Certificates
Mortgage Pass-Through Certificates
2005-A1

May 25, 2005 Distribution

CHARACTERISTICS
CHARACTERISTICS
														Total
Weighted Average Coupon Original														6.29509%
Weighted Average Coupon Prior														6.29445%
Weighted Average Coupon Current														6.29009%
Weighted Average Months to Maturity Original														356
Weighted Average Months to Maturity Prior														355
Weighted Average Months to Maturity Current														354
Weighted Avg Remaining Amortization Term Original														356
Weighted Avg Remaining Amortization Term Prior														355
Weighted Avg Remaining Amortization Term Current														354
Weighted Average Seasoning Original														3.52
Weighted Average Seasoning Prior														4.53
Weighted Average Seasoning Current														5.52









Page 8 of 22
IndyMac Residential Asset Securitization Trust 2005-A1

Mortgage Pass-Through Certificates
Mortgage Pass-Through Certificates
2005-A1

May 25, 2005 Distribution

ARM CHARACTERISTICS
ARM CHARACTERISTICS
														Total
Weighted Average Margin Original														0.00000%
Weighted Average Margin Prior														0.00000%
Weighted Average Margin Current														0.00000%
Weighted Average Max Rate Original														0.00000%
Weighted Average Max Rate Prior														0.00000%
Weighted Average Max Rate Current														0.00000%
Weighted Average Min Rate Original														0.00000%
Weighted Average Min Rate Prior														0.00000%
Weighted Average Min Rate Current														0.00000%
Weighted Average Cap Up Original														0.00000%
Weighted Average Cap Up Prior														0.00000%
Weighted Average Cap Up Current														0.00000%
Weighted Average Cap Down Original														0.00000%
Weighted Average Cap Down Prior														0.00000%
Weighted Average Cap Down Current														0.00000%




SERVICING FEES & ADVANCES

															Total




Current Servicing Fees														22,826.01
Delinquent Servicing Fees														78,464.80
TOTAL SERVICING FEES														101,290.81


Total Servicing Fees														101,290.81
Compensating Interest														-1,403.40
Delinquent Servicing Fees														-78,464.80
COLLECTED SERVICING FEES														21,422.61


Total Advaced Interest														1,496,653.69
Total Advaced Principal														260,669.64
Aggregate Advances with respect to this Distribution														1,757,323.33





ADDITIONAL COLLATERAL INFORMATION
														Total
Prepayment Interest Shortfall (PPIS)														1,403.40
Compensating Interest														-1,403.40
Net Prepayment Interest Shortfall (PPIS)														0.00

Weighted Average Net Mortgage Rate														5.929641%






Page 9 of 22
IndyMac Residential Asset Securitization Trust 2005-A1

Mortgage Pass-Through Certificates
Mortgage Pass-Through Certificates
2005-A1

May 25, 2005 Distribution
Delinquency Report

	TOTAL
					< 1 PAYMENT		1 PAYMENT		2 PAYMENTS		3+ PAYMENTS		TOTAL
	DELINQUENT		Balance				#######		810,703.85		0.00		5,018,221.16
			% Balance				1.10%		0.21%		0.00%		1.32%
			# Loans				11		3		0		14
			% # Loans				1.01%		0.28%		0.00%		1.29%
	FORECLOSURE		Balance		0.00		0.00		0.00		0.00		0.00
			% Balance		0.00%		0.00%		0.00%		0.00%		0.00%
			# Loans		0		0		0		0		0
			% # Loans		0.00%		0.00%		0.00%		0.00%		0.00%
	BANKRUPTCY		Balance		309,972.01		0.00		0.00		0.00		309,972.01
			% Balance		0.08%		0.00%		0.00%		0.00%		0.08%
			# Loans		2		0		0		0		2
			% # Loans		0.18%		0.00%		0.00%		0.00%		0.18%
	REO		Balance		0.00		0.00		0.00		0.00		0.00
			% Balance		0.00%		0.00%		0.00%		0.00%		0.00%
			# Loans		0		0		0		0		0
			% # Loans		0.00%		0.00%		0.00%		0.00%		0.00%
	TOTAL		Balance		309,972.01		4,207,517.31		810,703.85		0.00		5,328,193.17
			% Balance		0.08%		1.10%		0.21%		0.00%		1.40%
			# Loans		2		11		3		0		16
			% # Loans		0.18%		1.01%		0.28%		0.00%		1.47%









Page 10 of 22
IndyMac Residential Asset Securitization Trust 2005-A1

Mortgage Pass-Through Certificates
Mortgage Pass-Through Certificates
2005-A1

May 25, 2005 Distribution
REO Report
Loan Number			Original		Stated				Current		State &

														First
&			Principal		Principal		Paid to		Note		LTV at		Original		Payment

Loan Group			Balance		Balance		Date		Rate		Origination		Term		Date




TOTAL



Page 11 of 22
IndyMac Residential Asset Securitization Trust 2005-A1

Mortgage Pass-Through Certificates
Mortgage Pass-Through Certificates
2005-A1

May 25, 2005 Distribution
Foreclosure Report
Loan Number			Original		Stated				Current		State &

														First
&			Principal		Principal		Paid to		Note		LTV at		Original		Payment

Loan Group			Balance		Balance		Date		Rate		Origination		Term		Date




TOTAL



Page 12 of 22
IndyMac Residential Asset Securitization Trust 2005-A1

Mortgage Pass-Through Certificates
Mortgage Pass-Through Certificates
2005-A1

May 25, 2005 Distribution
Prepayment Report

VOLUNTARY PREPAYMENTS
VOLUNTARY PREPAYMENTS

															Total




Current


Number of Paid in Full Loans														14
Number of Repurchased Loans														0
Total Number of Loans Prepaid in Full														14
Curtailments Amount														30,099.85
Paid in Full Balance														6,540,240.82
Repurchased Loans Balance														0.00
Total Prepayment Amount														6,570,340.67

Cumulative


Number of Paid in Full Loans														46
Number of Repurchased Loans														13
Total Number of Loans Prepaid in Full														59
Paid in Full Balance														17,452,837.52
Repurchased Loans Balance														602,710.54
Curtailments Amount														83,047.38
Total Prepayment Amount														18,138,595.44










Page 13 of 22
IndyMac Residential Asset Securitization Trust 2005-A1

Mortgage Pass-Through Certificates
Mortgage Pass-Through Certificates
2005-A1

May 25, 2005 Distribution

VOLUNTARY PREPAYMENTS RATES
VOLUNTARY PREPAYMENTS RATES

															Total



SMM														1.70%
3 Months Avg SMM														1.58%
12 Months Avg SMM														1.58%
Avg SMM Since Cut-off														1.58%


CPR														18.55%
3 Months Avg CPR														17.41%
12 Months Avg CPR														17.41%
Avg CPR Since Cut-off														17.41%


PSA														1,679.28%
3 Months Avg PSA Approximation														1,923.65%
12 Months Avg PSA Approximation														1,923.65%
Avg PSA Since Cut-off Approximation														1,923.65%










Page 14 of 22
IndyMac Residential Asset Securitization Trust 2005-A1

Mortgage Pass-Through Certificates
Mortgage Pass-Through Certificates
2005-A1

May 25, 2005 Distribution






PREPAYMENT CALCULATION METHODOLOGY

Single Monthly Mortality (SMM): (Voluntary partial and full prepayments + Repurchases + Liquidations )/(Beg Principal Balance - Sched Principal) Conditional Prepayment Rate (CPR): 1-((1-SMM)^12) PSA Standard Prepayment Model: CPR/(0.002min(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) Conditional Prepayment Rate (CPR): 1-((1-SMM)^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) Dates correspond to distribution dates. Note: Prepayment rates are calculated since deal issue date and include partial and full voluntary prepayments, liquidations, and repurchases.













Page 15 of 22
IndyMac Residential Asset Securitization Trust 2005-A1

Mortgage Pass-Through Certificates
Mortgage Pass-Through Certificates
2005-A1

May 25, 2005 Distribution
Prepayment Detail Report
Prepayment Detail Report - Mortgage Loans Prepaid in Full During Current Distribution
Loan Number			Original							Current		State &		Type Prepayment		First
Loan Number			Original							Current		State &		Type Prepayment

&		Loan	Principal		Prepayment			Prepayment		Note		LTV at		&		Payment

Loan Group		Status	Balance		Amount			Date		Rate		Origination		Original Term		Date

2555708 1			203,000.00		199,347.24			11-May-2005		6.250%		MA - 51.13%		Paid Off - 360		01-Sep-2003
			203,000.00

3262349 1			364,500.00		358,983.73			04-May-2005		6.375%		NJ - 90.00%		Paid Off - 360		01-Dec-2003
3262349 1					358,983.73			04-May-2005		6.375%		NJ - 90.00%		Paid Off - 360		01-Dec-2003
120186292 1			99,000.00		98,501.28			25-Apr-2005		7.750%		SC - 94.29%		Paid Off - 360		01-Oct-2004
120186292 1					98,501.28			25-Apr-2005		7.750%		SC - 94.29%		Paid Off - 360		01-Oct-2004
120374788 1			425,000.00		425,000.00			13-May-2005		5.875%		CA - 74.69%		Paid Off - 360		01-Dec-2004
120374788 1					425,000.00			13-May-2005		5.875%		CA - 74.69%		Paid Off - 360		01-Dec-2004
120377865 1			648,000.00		645,312.98			02-May-2005		7.000%		CO - 80.00%		Paid Off - 360		01-Dec-2004
120377865 1					645,312.98			02-May-2005		7.000%		CO - 80.00%		Paid Off - 360		01-Dec-2004
120378956 1			410,000.00		407,889.40			10-May-2005		5.875%		CA - 56.55%		Paid Off - 360		01-Dec-2004
120378956 1					407,889.40			10-May-2005		5.875%		CA - 56.55%		Paid Off - 360		01-Dec-2004
120380244 1			675,000.00		672,226.95			26-Apr-2005		5.875%		WA - 42.45%		Paid Off - 360		01-Jan-2005
120380244 1					672,226.95			26-Apr-2005		5.875%		WA - 42.45%		Paid Off - 360		01-Jan-2005
120380522 1			362,000.00		362,000.00			12-May-2005		7.000%		MD - 46.41%		Paid Off - 360		01-Feb-2005
120380522 1					362,000.00			12-May-2005		7.000%		MD - 46.41%		Paid Off - 360		01-Feb-2005
120531310 1			416,000.00		414,837.95			10-May-2005		6.375%		CA - 80.00%		Paid Off - 360		01-Feb-2005
120531310 1					414,837.95			10-May-2005		6.375%		CA - 80.00%		Paid Off - 360		01-Feb-2005
120597663 1			130,000.00		129,636.87			10-May-2005		6.375%		CA - 52.00%		Paid Off - 360		01-Feb-2005
120597663 1					129,636.87			10-May-2005		6.375%		CA - 52.00%		Paid Off - 360		01-Feb-2005
120598636 1			118,750.00		118,591.07			02-May-2005		10.000%		FL - 95.00%		Paid Off - 360		01-Feb-2005
120598636 1					118,591.07			02-May-2005		10.000%		FL - 95.00%		Paid Off - 360		01-Feb-2005
120652133 1			516,000.00		514,523.54			22-Apr-2005		6.250%		CA - 77.01%		Paid Off - 360		01-Feb-2005
120652133 1					514,523.54			22-Apr-2005		6.250%		CA - 77.01%		Paid Off - 360		01-Feb-2005
120718644 1			1,810,000.00		1,804,695.39			09-May-2005		6.125%		CA - 62.41%		Paid Off - 360		01-Feb-2005
120718644 1					1,804,695.39			09-May-2005		6.125%		CA - 62.41%		Paid Off - 360		01-Feb-2005
120827723 1			389,600.00		388,694.42			03-May-2005		7.750%		NC - 75.50%		Paid Off - 360		01-Feb-2005
120827723 1					388,694.42			03-May-2005		7.750%		NC - 75.50%		Paid Off - 360		01-Feb-2005


TOTAL			6,566,850.00		6,540,240.82
TOTAL


Page 16 of 22
IndyMac Residential Asset Securitization Trust 2005-A1

Mortgage Pass-Through Certificates
Mortgage Pass-Through Certificates
2005-A1

May 25, 2005 Distribution
Realized Loss Report

COLLATERAL REALIZED LOSSES



															Total


Current
Current



Number of Loans Liquidated														0
Collateral Principal Realized Loss/(Gain) Amount														0.00
Collateral Interest Realized Loss/(Gain) Amount														0.00
Net Liquidation Proceeds														0.00

Cumulative
Cumulative



Number of Loans Liquidated														0
Collateral Realized Loss/(Gain) Amount														0.00
Net Liquidation Proceeds														0.00





		Special Hazard Loss Coverage Amt														3,877,874.47
		Fraud Loss Coverage Amt														4,000,000.00
		Bankrupt Loss Coverage Amt														100,000.00
		Class B-1 Writedown Amount														0.00
		Class B-2 Writedown Amount														0.00
		Class B-3 Writedown Amount														0.00
		Class B-4 Writedown Amount														0.00
		Class B-5 Writedown Amount														0.00
		Class B-6 Writedown Amount														0.00









Page 17 of 22
IndyMac Residential Asset Securitization Trust 2005-A1

Mortgage Pass-Through Certificates
Mortgage Pass-Through Certificates
2005-A1

May 25, 2005 Distribution


DEFAULT SPEEDS



															Total



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


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


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


Loss Severity Approximation for Current Period														0.00%
3 Months Avg Loss Severity Approximation														0.00%
12 Months Avg Loss Severity Approximation														0.00%
Avg Loss Severity Approximation Since Cut-off														0.00%












Page 18 of 22
IndyMac Residential Asset Securitization Trust 2005-A1

Mortgage Pass-Through Certificates
Mortgage Pass-Through Certificates
2005-A1

May 25, 2005 Distribution





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 19 of 22
IndyMac Residential Asset Securitization Trust 2005-A1

Mortgage Pass-Through Certificates
Mortgage Pass-Through Certificates
2005-A1

May 25, 2005 Distribution
Realized Loss Detail Report
Loan Number			Current		State &				Prior		Realized				Cumulative
															Cumulative
&		Loan	Note		LTV at		Original		Principal		Loss/(Gain)		Realized		Realized

Loan Group		Status	Rate		Origination		Term		Balance		Revision		Loss/(Gain)		Loss/(Gain)
Loan Group		Status	Rate		Origination		Term		Balance		Revision		Loss/(Gain)		Loss/(Gain)




TOTAL



Page 20 of 22
IndyMac Residential Asset Securitization Trust 2005-A1

Mortgage Pass-Through Certificates
Mortgage Pass-Through Certificates
2005-A1

May 25, 2005 Distribution
Triggers and Adj. Cert. Report
TRIGGER EVENTS
TRIGGER EVENTS
														Total
						Has Optional Termination Date Reached (0=No,1=Yes)								0
						Has Sr. Prepay Stepdown Condition Occurred								0
						Has Sr. Credit Supp. Depletion Date Occured								0
						Have all Prepayment Penalties Expired? (0=No,1=Yes)								0
						Has Special Haz. Cov. Term Date Occured								0
						Has Fraud Loss Coverage Term Date Occured								0
						Has BK Loss Cov. Term Date Occured (0=No,1=Yes)								0



ADJUSTABLE RATE CERTIFICATE INFORMATION

SPACE INTENTIONALLY LEFT BLANK



ADDITIONAL INFORMATION
ADDITIONAL INFORMATION
														Total
Current Senior Percentage														95.107692%
Next Senior Percentage														95.023173%
Current Subordinate Percentage														4.892308%
Next Subordinate Percentage														4.976827%
Senior Prepayment Percentage														100.000000%
Next Senior Prepayment Percentage														100.000000%
Subordinate Prepayment Percentage														0.000000%
Next Subordinate Prepayment Percentage														0.000000%




Page 21 of 22
IndyMac Residential Asset Securitization Trust 2005-A1

Mortgage Pass-Through Certificates
Mortgage Pass-Through Certificates
2005-A1

May 25, 2005 Distribution
Other Related Information
ADDITIONAL INFORMATION
ADDITIONAL INFORMATION
														Total
Current Scheduled Payments														2,362,778.38
Current Scheduled Payments 1 Month Prior														2,411,124.21
Current Scheduled Payments 2 Month Prior														2,144,936.62
Current Scheduled Payments 3 Month Prior														0.00
Current Scheduled Payments 4 Month Prior														0.00
Current Scheduled Payments 5 Month Prior														0.00
Current Scheduled Payments 6 Month Prior														0.00
Current Scheduled Payments 7 Month Prior														0.00
Current Scheduled Payments 8 Month Prior														0.00
Current Scheduled Payments 9 Month Prior														0.00
Current Scheduled Payments 10 Month Prior														0.00
Current Scheduled Payments 11 Month Prior														0.00


Delinquent 60+ Scheduled Payments														7,581.20
Delinq. 60+ Sched. Pmnts, 1 Month Prior														4,245.07
Delinq. 60+ Sched. Pmnts, 2 Month Prior														1,118.61
Delinq. 60+ Sched. Pmnts, 3 Month Prior														0.00
Delinq. 60+ Sched. Pmnts, 4 Month Prior														0.00
Delinq. 60+ Sched. Pmnts, 5 Month Prior														0.00
Delinq. 60+ Sched. Pmnts, 6 Month Prior														0.00
Delinq. 60+ Sched. Pmnts, 7 Month Prior														0.00
Delinq. 60+ Sched. Pmnts, 8 Month Prior														0.00
Delinq. 60+ Sched. Pmnts, 9 Month Prior														0.00
Delinq. 60+ Sched. Pmnts, 10 Month Prior														0.00
Delinq. 60+ Sched. Pmnts, 11 Month Prior														0.00


Variable Rate Certificates - Next PTR Details:
Next Period Pass Through Rate - Class A-X														0.600500%




Page 22 of 22

IndyMac MBS, Inc. Residential Asset Securitization Trust 2005-A1 8-K