8-K 1 mss04001_dec.txt DEC. 8-K 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): December 27, 2004 MASTR SEASONED SECURITIZATION TRUST Mortgage Pass-Through Certificates, Series 2004-1 Trust (Exact name of registrant as specified in its charter) New York (governing law of 333-106982-45 Pooling and Servicing Agreement) (Commission 54-2161224 (State or other File Number) 54-2161225 jurisdiction IRS EIN of Incorporation) c/o Wells Fargo Bank, N.A. 9062 Old Annapolis Road Columbia, MD 21045, MD 21045 (Address of principal executive offices) (Zip Code) Registrant's telephone number, including area code: (410) 884-2000 (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 under the Exchange Act (17 CFR 240.14a-12) [ ] 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 On December 27, 2004 a distribution was made to holders of MASTR SEASONED SECURITIZATION TRUST, Mortgage Pass-Through Certificates, Series 2004-1 Trust. ITEM 9.01 Financial Statements and Exhibits (c) Exhibits Exhibit Number Description EX-99.1 Monthly report distributed to holders of Mortgage Pass-Through Certificates, Series 2004-1 Trust, relating to the December 27, 2004 distribution. 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. MASTR SEASONED SECURITIZATION TRUST Mortgage Pass-Through Certificates, Series 2004-1 Trust (Registrant) By: Wells Fargo Bank, N.A. as Master Servicer By: /s/ Beth Belfield as Assistant Vice President By: Beth Belfield as Assistant Vice President Date: 1/6/05 INDEX TO EXHIBITS Exhibit Number Description EX-99.1 Monthly report distributed to holders of Mortgage Pass-Through Certificates, Series 2004-1 Trust, relating to the December 27, 2004 distribution. EX-99.1

~~SECURITIES~~MASTR ~~AND~~Seasoned ~~EXCHANGE~~Securitization ~~COMMISSION~~Trust Mortgage Pass-Through Certificates Record Date: 11/30/04 Distribution Date: 12/27/04 MASTR Seasoned Securitization Trust Mortgage Pass-Through Certificates Series 2004-1 Contact: Customer Service - CTSLink Wells Fargo Bank, N.A. Securities Administration Services 7485 New Horizon Way Frederick, MD 21703 Telephone: (301) 815-6600 Fax: (301) 815-6660 Certificateholder Distribution Summary Certificate Certificate Beginning Class Pass-Through Certificate Interest Principal Class CUSIP Description Rate Balance Distribution Distribution 1-A-1 55265WAV5 SEN 6.24996% 128,063,271.31 666,497.01 4,639,362.92 2-A-1 55265WAW3 SEN 8.00000% 193,512,750.70 1,289,404.54 7,960,831.99 2-A-2 55265WAX1 SEN 5.50000% 47,790,720.48 218,925.27 1,966,040.45 2-A-3 55265WAY9 SEN 5.25000% 47,790,720.48 208,974.12 1,966,040.45 2-A-4 55265WAZ6 SEN 5.00000% 121,826,671.89 507,343.39 5,011,771.39 2-A-5 55265WBA0 SEN 6.50000% 0.00 0.00 0.00 2-A-6 55265WBB8 SEN 6.50000% 500,000.00 2,706.90 0.00 3-A-1 55265WBC6 SEN 4.67219% 34,573,797.63 134,541.71 1,670,333.73 4-A-1 55265WBD4 SEN 5.23139% 64,049,862.62 279,077.61 2,299,736.76 4-A-2 55265WBE2 SEN 5.23139% 3,370,625.79 14,686.47 121,023.71 A-X 55265WBF9 IO 6.50000% 0.00 108,957.59 0.00 PO 55265WBZ5 PO 0.00000% 3,793,817.24 0.00 158,463.20 A-LR 55265WBG7 RES 6.25265% 0.00 0.00 0.00 A-UR 55265WBH5 RES 6.25265% 0.00 0.00 0.00 15-B-1 55265WBJ1 SUB 6.24996% 549,350.69 2,859.06 2,882.53 15-B-2 55265WBK8 SUB 6.24996% 274,180.44 1,426.95 1,438.67 15-B-3 55265WBL6 SUB 6.24996% 205,882.78 1,071.50 1,080.30 30-B-1 55265WBM4 SUB 6.50000% 8,851,848.59 47,919.54 10,719.36 30-B-2 55265WBN2 SUB 6.50000% 931,773.54 5,044.16 1,128.35 30-B-3 55265WBP7 SUB 6.50000% 698,331.34 3,780.42 845.66 HY-B-1 55265WBQ5 SUB 5.03521% 2,344,443.39 9,831.57 3,273.46 HY-B-2 55265WBR3 SUB 5.03521% 481,652.98 2,019.84 672.51 HY-B-3 55265WBS1 SUB 5.03521% 180,495.22 756.92 252.02 15-B-4 55265WBT9 SUB 6.24996% 137,585.13 716.05 721.93 15-B-5 55265WBU6 SUB 6.24996% 68,297.65 355.45 358.37 15-B-6 55265WBV4 SUB 6.24996% 138,213.38 719.32 725.23 C-B-4 55265WBW2 SUB 6.20094% 586,549.47 3,029.20 732.58 C-B-5 55265WBX0 SUB 6.20094% 293,274.74 1,514.60 366.29 C-B-6 55265WBY8 SUB 6.20094% 586,473.19 3,028.80 730.89 Totals 661,600,590.67 3,515,187.99 25,819,532.75

~~WASHINGTON~~Certificateholder Distribution Summary (continued) Current Ending Cumulative Realized Certificate Total Realized Class Loss Balance Distribution Losses 1-A-1 0.00 123,423,908.39 D5,305,859.93 0.00 2-A-1 0.00 185,551,918.71 9,250,236.53 0.00 2-A-2 0.00 45,824,680.03 2,184,965.72 0.00 2-A-3 0.00 45,824,680.03 2,175,014.57 0.00 2-A-4 0.00 116,814,900.50 5,519,114.78 0.00 2-A-5 0.00 0.00 0.00 0.00 2-A-6 0.00 500,000.00 2,706.90 0.00 3-A-1 0.00 32,903,463.90 1,804,875.44 0.00 4-A-1 0.00 61,750,125.87 2,578,814.37 0.00 4-A-2 0.00 3,249,602.08 135,710.18 0.00 A-X 0.00 0.00 108,957.59 0.00 PO 0.00 3,635,354.04 158,463.20 0.00 A-LR 0.00 0.00 0.00 0.00 A-UR 0.00 0.00 0.00 0.00 15-B-1 0.00 546,468.16 5,741.59 0.00 15-B-2 0.00 272,741.77 2,865.62 0.00 15-B-3 0.00 204,802.48 2,151.80 0.00 30-B-1 0.00 8,841,129.23 58,638.90 0.00 30-B-2 0.00 930,645.18 6,172.51 0.00 30-B-3 0.00 697,485.68 4,626.08 0.00 HY-B-1 0.00 2,341,169.93 13,105.03 0.00 HY-B-2 0.00 480,980.47 2,692.35 0.00 HY-B-3 0.00 180,243.20 1,008.94 0.00 15-B-4 0.00 136,863.20 1,437.98 0.00 15-B-5 0.00 67,939.28 713.82 0.00 15-B-6 0.00 137,488.15 1,444.55 0.00 C-B-4 0.00 ~~20549~~585,816.89 3,761.78 0.00 C-B-5 0.00 292,908.44 1,880.89 0.00 C-B-6 0.00 585,742.29 3,759.69 0.00 Totals 0.00 635,781,057.90 29,334,720.74 0.00 All distributions required by the Pooling and Servicing Agreement have been calculated by the Certificate Administrator on behalf of the Trustee.

~~FORM~~Principal Distribution Statement Original Beginning Scheduled Unscheduled Face Certificate Principal Principal Realized Class Amount Balance Distribution Distribution Accretion Loss (1) 1-A-1 137,304,000.00 128,063,271.31 671,968.29 3,967,394.63 0.00 0.00 2-A-1 202,458,499.00 193,512,750.70 234,624.08 7,726,207.91 0.00 0.00 2-A-2 50,000,000.00 47,790,720.48 57,943.75 1,908,096.71 0.00 0.00 2-A-3 50,000,000.00 47,790,720.48 57,943.75 1,908,096.71 0.00 0.00 2-A-4 127,458,501.00 121,826,671.89 147,708.46 4,864,062.92 0.00 0.00 2-A-5 20,927,000.00 0.00 0.00 0.00 0.00 0.00 2-A-6 500,000.00 500,000.00 0.00 0.00 0.00 0.00 3-A-1 41,159,000.00 34,573,797.63 48,700.52 1,621,633.21 0.00 0.00 4-A-1 72,304,000.00 64,049,862.62 89,003.41 2,210,733.35 0.00 0.00 4-A-2 3,805,000.00 3,370,625.79 4,683.81 116,339.90 0.00 0.00 A-X 0.00 0.00 0.00 0.00 0.00 0.00 PO 3,989,934.02 3,793,817.24 5,682.29 152,780.91 0.00 0.00 A-LR 50.00 0.00 0.00 0.00 0.00 0.00 A-UR 50.00 0.00 0.00 0.00 0.00 0.00 15-B-1 555,000.00 549,350.69 2,882.53 0.00 0.00 0.00 15-B-2 277,000.00 274,180.44 1,438.67 0.00 0.00 0.00 15-B-3 208,000.00 205,882.78 1,080.30 0.00 0.00 0.00 30-B-1 8,873,000.00 8,851,848.59 10,719.36 0.00 0.00 0.00 30-KB-2 934,000.00 931,773.54 1,128.35 0.00 0.00 0.00 30-B-3 700,000.00 698,331.34 845.66 0.00 0.00 0.00 HY-B-1 2,351,000.00 2,344,443.39 3,273.46 0.00 0.00 0.00 HY-B-2 483,000.00 481,652.98 672.51 0.00 0.00 0.00 HY-B-3 181,000.00 180,495.22 252.02 0.00 0.00 0.00 15-B-4 139,000.00 137,585.13 721.93 0.00 0.00 0.00 15-B-5 69,000.00 68,297.65 358.37 0.00 0.00 0.00 15-B-6 139,634.71 138,213.38 725.23 0.00 0.00 0.00 C-B-4 588,000.00 586,549.47 732.58 0.00 0.00 0.00 C-B-5 294,000.00 293,274.74 366.29 0.00 0.00 0.00 C-B-6 587,921.83 586,473.19 730.89 0.00 0.00 0.00 Totals 726,285,590.56 661,600,590.67 1,344,186.51 24,475,346.25 0.00 0.00 (1) Amount Does Not Include Excess Special Hazard, Bankruptcy, or Fraud Losses Unless Otherwise Disclosed. Please Refer to the Prospectus Supplement for a Full Description.

~~CURRENT~~Principal ~~REPORT~~Distribution Statement (continued) Total Ending Ending Total Principal Certificate Certificate Principal Class Reduction Balance Percentage Distribution 1-A-1 4,639,362.92 123,423,908.39 0.89890978 4,639,362.92 2-A-1 7,960,831.99 185,551,918.71 0.91649360 7,960,831.99 2-A-2 1,966,040.45 45,824,680.03 0.91649360 1,966,040.45 2-A-3 1,966,040.45 45,824,680.03 0.91649360 1,966,040.45 2-A-4 5,011,771.39 116,814,900.50 0.91649360 5,011,771.39 2-A-5 0.00 0.00 0.00000000 0.00 2-A-6 0.00 500,000.00 1.00000000 0.00 3-A-1 1,670,333.73 32,903,463.90 0.79942331 1,670,333.73 4-A-1 2,299,736.76 61,750,125.87 0.85403471 2,299,736.76 4-A-2 121,023.71 3,249,602.08 0.85403471 121,023.71 A-X 0.00 0.00 0.00000000 0.00 PO 158,463.20 3,635,354.04 0.91113137 158,463.20 A-LR 0.00 0.00 0.00000000 0.00 A-UR 0.00 0.00 0.00000000 0.00 15-B-1 2,882.53 546,468.16 0.98462732 2,882.53 15-B-2 1,438.67 272,741.77 0.98462733 1,438.67 15-B-3 1,080.30 204,802.48 0.98462731 1,080.30 30-B-1 10,719.36 8,841,129.23 0.99640812 10,719.36 30-B-2 1,128.35 930,645.18 0.99640812 1,128.35 30-B-3 845.66 697,485.68 0.99640811 845.66 HY-B-1 3,273.46 2,341,169.93 0.99581877 3,273.46 HY-B-2 672.51 480,980.47 0.99581878 672.51 HY-B-3 252.02 180,243.20 0.99581878 252.02 15-B-4 721.93 136,863.20 0.98462734 721.93 15-B-5 358.37 67,939.28 0.98462725 358.37 15-B-6 725.23 137,488.15 0.98462732 725.23 C-B-4 732.58 585,816.89 0.99628723 732.58 C-B-5 366.29 292,908.44 0.99628721 366.29 C-B-6 730.89 585,742.29 0.99629281 730.89 Totals 25,819,532.75 635,781,057.90 0.87538713 25,819,532.75

~~Pursuant~~Principal toDistribution ~~Section~~Factors 13Statement orOriginal Beginning Scheduled Unscheduled Face Certificate Principal Principal Class (2) Amount Balance Distribution Distribution Accretion 1-A-1 137,304,000.00 932.69876559 4.89401831 28.89496759 0.00000000 2-A-1 202,458,499.00 955.81440965 1.15887494 38.16193417 0.00000000 2-A-2 50,000,000.00 955.81440960 1.15887500 38.16193420 0.00000000 2-A-3 50,000,000.00 955.81440960 1.15887500 38.16193420 0.00000000 2-A-4 127,458,501.00 955.81440966 1.15887492 38.16193413 0.00000000 2-A-5 20,927,000.00 0.00000000 0.00000000 0.00000000 0.00000000 2-A-6 500,000.00 1000.00000000 0.00000000 0.00000000 0.00000000 3-A-1 41,159,000.00 840.00577346 1.18322894 39.39923735 0.00000000 4-A-1 72,304,000.00 885.84120685 1.23096108 30.57553317 0.00000000 4-A-2 3,805,000.00 885.84120631 1.23096189 30.57553219 0.00000000 A-X 0.00 0.00000000 0.00000000 0.00000000 0.00000000 PO 3,989,934.02 950.84711200 1.42415638 38.29158809 0.00000000 A-LR 50.00 0.00000000 0.00000000 0.00000000 0.00000000 A-UR 50.00 0.00000000 0.00000000 0.00000000 0.00000000 15-B-1 555,000.00 989.82106306 5.19374775 0.00000000 0.00000000 15-B-2 277,000.00 989.82108303 5.19375451 0.00000000 0.00000000 15-B-3 208,000.00 989.82105769 5.19375000 0.00000000 0.00000000 30-B-1 8,873,000.00 997.61620534 1.20808746 0.00000000 0.00000000 30-B-2 934,000.00 997.61620985 1.20808351 0.00000000 0.00000000 30-B-3 700,000.00 997.61620000 1.20808571 0.00000000 0.00000000 HY-B-1 2,351,000.00 997.21113994 1.39236920 0.00000000 0.00000000 HY-B-2 483,000.00 997.21113872 1.39236025 0.00000000 0.00000000 HY-B-3 181,000.00 997.21116022 1.39237569 0.00000000 0.00000000 15-B-4 139,000.00 989.82107914 5.19374101 0.00000000 0.00000000 15-B-5 69,000.00 989.82101449 5.19376812 0.00000000 0.00000000 15-B-6 139,634.71 989.82108388 5.19376593 0.00000000 0.00000000 C-B-4 588,000.00 997.53311224 1.24588435 0.00000000 0.00000000 C-B-5 294,000.00 997.53312925 1.24588435 0.00000000 0.00000000 C-B-6 587,921.83 997.53599896 1.24317547 0.00000000 0.00000000 (d2) ofAll ~~the~~Classes are per $1,000 denomination

~~Securities~~Principal ~~Exchange~~Distribution ~~Act~~Factors ofStatement ~~1934~~(continued) Total Ending Ending Total Realized Principal Certificate Certificate Principal Class Loss (3) Reduction Balance Percentage Distribution 1-A-1 0.00000000 33.78898590 898.90977969 0.89890978 33.78898590 2-A-1 0.00000000 39.32080910 916.49360055 0.91649360 39.32080910 2-A-2 0.00000000 39.32080900 916.49360060 0.91649360 39.32080900 2-A-3 0.00000000 39.32080900 916.49360060 0.91649360 39.32080900 2-A-4 0.00000000 39.32080913 916.49360053 0.91649360 39.32080913 2-A-5 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 2-A-6 0.00000000 0.00000000 1,000.00000000 1.00000000 0.00000000 3-A-1 0.00000000 40.58246629 799.42330717 0.79942331 40.58246629 4-A-1 0.00000000 31.80649425 854.03471274 0.85403471 31.80649425 4-A-2 0.00000000 31.80649409 854.03471222 0.85403471 31.80649409 A-X 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 PO 0.00000000 39.71574447 911.13136753 0.91113137 39.71574447 A-LR 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 A-UR 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 15-B-1 0.00000000 5.19374775 984.62731532 0.98462732 5.19374775 15-B-2 0.00000000 5.19375451 984.62732852 0.98462733 5.19375451 15-B-3 0.00000000 5.19375000 984.62730769 0.98462731 5.19375000 30-B-1 0.00000000 1.20808746 996.40811789 0.99640812 1.20808746 30-B-2 0.00000000 1.20808351 996.40811563 0.99640812 1.20808351 30-B-3 0.00000000 1.20808571 996.40811429 0.99640811 1.20808571 HY-B-1 0.00000000 1.39236920 995.81877074 0.99581877 1.39236920 HY-B-2 0.00000000 1.39236025 995.81877847 0.99581878 1.39236025 HY-B-3 0.00000000 1.39237569 995.81878453 0.99581878 1.39237569 15-B-4 0.00000000 5.19374101 984.62733813 0.98462734 5.19374101 15-B-5 0.00000000 5.19376812 984.62724638 0.98462725 5.19376812 15-B-6 0.00000000 5.19376593 984.62731795 0.98462732 5.19376593 C-B-4 0.00000000 1.24588435 996.28722789 0.99628723 1.24588435 C-B-5 0.00000000 1.24588435 996.28721088 0.99628721 1.24588435 C-B-6 0.00000000 1.24317547 996.29280648 0.99629281 1.24317547 (3) Amount Does Not Include Excess Special Hazard, Bankruptcy, or Fraud Losses Unless Otherwise Disclosed. Please Refer to the Prospectus Supplement for a Full Description.

~~Date~~Interest ofDistribution ~~Report~~Statement ~~(Date~~Beginning Payment of ~~earliest~~Original ~~event~~Current ~~reported):~~Certificate/ ~~September~~Current Unpaid Current Face Certificate Notional Accrued Interest Interest Class Amount Rate Balance Interest Shortfall Shortfall 1-A-1 137,304,000.00 6.24996% 128,063,271.31 666,992.01 0.00 0.00 2-A-1 202,458,499.00 8.00000% 193,512,750.70 1,290,085.00 0.00 0.00 2-A-2 50,000,000.00 5.50000% 47,790,720.48 219,040.80 0.00 0.00 2-A-3 50,000,000.00 5.25000% 47,790,720.48 209,084.40 0.00 0.00 2-A-4 127,458,501.00 5.00000% 121,826,671.89 507,611.13 0.00 0.00 2-A-5 20,927,000.00 6.50000% 0.00 0.00 0.00 0.00 2-A-6 500,000.00 6.50000% 500,000.00 2,708.33 0.00 0.00 3-A-1 41,159,000.00 4.67219% 34,573,797.63 134,612.72 0.00 0.00 4-A-1 72,304,000.00 5.23139% 64,049,862.62 279,224.89 0.00 0.00 4-A-2 3,805,000.00 5.23139% 3,370,625.79 14,694.22 0.00 0.00 A-X 0.00 6.50000% 20,125,905.50 109,015.32 0.00 0.00 PO 3,989,934.02 0.00000% 3,793,817.24 0.00 0.00 0.00 A-LR 50.00 6.25265% 0.00 0.00 0.00 0.00 A-UR 50.00 6.25265% 0.00 0.00 0.00 0.00 15-B-1 555,000.00 6.24996% 549,350.69 2,861.18 0.00 0.00 15-B-2 277,000.00 6.24996% 274,180.44 1,428.01 0.00 0.00 15-B-3 208,000.00 6.24996% 205,882.78 1,072.30 0.00 0.00 30-B-1 8,873,000.00 ~~2004~~6.50000% 8,851,848.59 47,947.51 0.00 0.00 30-B-2 934,000.00 6.50000% 931,773.54 5,047.11 0.00 0.00 30-B-3 700,000.00 6.50000% 698,331.34 3,782.63 0.00 0.00 HY-B-1 2,351,000.00 5.03521% 2,344,443.39 9,837.31 0.00 0.00 HY-B-2 483,000.00 5.03521% 481,652.98 2,021.02 0.00 0.00 HY-B-3 181,000.00 5.03521% 180,495.22 757.36 0.00 0.00 15-B-4 139,000.00 6.24996% 137,585.13 716.58 0.00 0.00 15-B-5 69,000.00 6.24996% 68,297.65 355.71 0.00 0.00 15-B-6 139,634.71 6.24996% 138,213.38 719.86 0.00 0.00 C-B-4 588,000.00 6.20094% 586,549.47 3,030.96 0.00 0.00 C-B-5 294,000.00 6.20094% 293,274.74 1,515.48 0.00 0.00 C-B-6 587,921.83 6.20094% 586,473.19 3,030.57 0.00 0.00 Totals 726,285,590.56 3,517,192.41 0.00 0.00

~~MORTGAGE~~Interest ~~ASSET~~Distribution ~~SECURITIZATION~~Statement ~~TRANSACTIONS~~(continued) Remaining Ending Non-Supported Total Unpaid Certificate/ Interest Realized Interest Interest Notional Class Shortfall Losses (4) Distribution Shortfall Balance 1-A-1 495.00 0.00 666,497.01 ~~INC~~0.00 123,423,908.39 2-A-1 680.46 0.00 1,289,404.54 0.00 185,551,918.71 2-A-2 115.53 0.00 218,925.27 0.00 45,824,680.03 2-A-3 110.28 0.00 208,974.12 0.00 45,824,680.03 2-A-4 267.74 0.00 507,343.39 0.00 116,814,900.50 2-A-5 0.00 0.00 0.00 0.00 0.00 2-A-6 1.43 0.00 2,706.90 0.00 500,000.00 3-A-1 71.00 0.00 134,541.71 0.00 32,903,463.90 4-A-1 147.28 0.00 279,077.61 0.00 61,750,125.87 4-A-2 7.75 0.00 14,686.47 0.00 3,249,602.08 A-X 57.73 0.00 108,957.59 0.00 19,318,788.95 PO 0.00 0.00 0.00 0.00 3,635,354.04 A-LR 0.00 0.00 0.00 0.00 0.00 A-UR 0.00 0.00 0.00 0.00 0.00 15-B-1 2.12 0.00 2,859.06 0.00 546,468.16 15-B-2 1.06 0.00 1,426.95 0.00 272,741.77 15-B-3 0.80 0.00 1,071.50 0.00 204,802.48 30-B-1 27.98 0.00 47,919.54 0.00 8,841,129.23 30-B-2 2.94 0.00 5,044.16 0.00 930,645.18 30-B-3 2.21 0.00 3,780.42 0.00 697,485.68 HY-B-1 5.74 0.00 9,831.57 0.00 2,341,169.93 HY-B-2 1.18 0.00 2,019.84 0.00 480,980.47 HY-B-3 0.44 0.00 756.92 0.00 180,243.20 15-B-4 0.53 0.00 716.05 0.00 136,863.20 15-B-5 0.26 0.00 355.45 0.00 67,939.28 15-B-6 0.53 0.00 719.32 0.00 137,488.15 C-B-4 1.77 0.00 3,029.20 0.00 585,816.89 C-B-5 0.88 0.00 1,514.60 0.00 292,908.44 C-B-6 1.77 0.00 3,028.80 0.00 585,742.29 Totals 2,004.41 0.00 3,515,187.99 0.00 (4) Amount Does Not Include Excess Special Hazard, Bankruptcy, or Fraud Losses Unless Otherwise Disclosed. Please Refer to the Prospectus Supplement for a Full Description.

Interest Distribution Factors Statement Beginning Payment of Original Current Certificate/ Current Unpaid Current Face Certificate Notional Accrued Interest Interest Class (as5) ~~depositor~~Amount ~~under~~Rate ~~the~~Balance ~~Pooling~~Interest ~~and~~Shortfall ~~Servicing~~Shortfall ~~Agreement~~1-A-1 137,304,000.00 6.24996% 932.69876559 4.85777552 0.00000000 0.00000000 2-A-1 202,458,499.00 8.00000% 955.81440965 6.37209604 0.00000000 0.00000000 2-A-2 50,000,000.00 5.50000% 955.81440960 4.38081600 0.00000000 0.00000000 2-A-3 50,000,000.00 5.25000% 955.81440960 4.18168800 0.00000000 0.00000000 2-A-4 127,458,501.00 5.00000% 955.81440966 3.98256002 0.00000000 0.00000000 2-A-5 20,927,000.00 6.50000% 0.00000000 0.00000000 0.00000000 0.00000000 2-A-6 500,000.00 6.50000% 1000.00000000 5.41666000 0.00000000 0.00000000 3-A-1 41,159,000.00 4.67219% 840.00577346 3.27055371 0.00000000 0.00000000 4-A-1 72,304,000.00 5.23139% 885.84120685 3.86181802 0.00000000 0.00000000 4-A-2 3,805,000.00 5.23139% 885.84120631 3.86181866 0.00000000 0.00000000 A-X 0.00 6.50000% 910.60101684 4.93242211 0.00000000 0.00000000 PO 3,989,934.02 0.00000% 950.84711200 0.00000000 0.00000000 0.00000000 A-LR 50.00 6.25265% 0.00000000 0.00000000 0.00000000 0.00000000 A-UR 50.00 6.25265% 0.00000000 0.00000000 0.00000000 0.00000000 15-B-1 555,000.00 6.24996% 989.82106306 5.15527928 0.00000000 0.00000000 15-B-2 277,000.00 6.24996% 989.82108303 5.15527076 0.00000000 0.00000000 15-B-3 208,000.00 6.24996% 989.82105769 5.15528846 0.00000000 0.00000000 30-B-1 8,873,000.00 6.50000% 997.61620534 5.40375409 0.00000000 0.00000000 30-B-2 934,000.00 6.50000% 997.61620985 5.40375803 0.00000000 0.00000000 30-B-3 700,000.00 6.50000% 997.61620000 5.40375714 0.00000000 0.00000000 HY-B-1 2,351,000.00 5.03521% 997.21113994 4.18430880 0.00000000 0.00000000 HY-B-2 483,000.00 5.03521% 997.21113872 4.18430642 0.00000000 0.00000000 HY-B-3 181,000.00 5.03521% 997.21116022 4.18430939 0.00000000 0.00000000 15-B-4 139,000.00 6.24996% 989.82107914 5.15525180 0.00000000 0.00000000 15-B-5 69,000.00 6.24996% 989.82101449 5.15521739 0.00000000 0.00000000 15-B-6 139,634.71 6.24996% 989.82108388 5.15530845 0.00000000 0.00000000 C-B-4 588,000.00 6.20094% 997.53311224 5.15469388 0.00000000 0.00000000 C-B-5 294,000.00 6.20094% 997.53312925 5.15469388 0.00000000 0.00000000 C-B-6 587,921.83 6.20094% 997.53599896 5.15471589 0.00000000 0.00000000 (5) All Classes are per $1,000 denomination

~~dated~~Interest asDistribution ofFactors ~~September~~Statement (continued) Remaining Ending Non-Supported Total Unpaid Certificate/ Interest Realized Interest Interest Notional Class Shortfall Losses (6) Distribution Shortfall Balance 1-A-1 0.00360514 0.00000000 4.85417038 0.00000000 898.90977969 2-A-1 0.00336099 0.00000000 6.36873506 0.00000000 916.49360055 2-A-2 0.00231060 0.00000000 4.37850540 0.00000000 916.49360060 2-A-3 0.00220560 0.00000000 4.17948240 0.00000000 916.49360060 2-A-4 0.00210061 0.00000000 3.98045941 0.00000000 916.49360053 2-A-5 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 2-A-6 0.00286000 0.00000000 5.41380000 0.00000000 1000.00000000 3-A-1 0.00172502 0.00000000 3.26882845 0.00000000 799.42330717 4-A-1 0.00203696 0.00000000 3.85978106 0.00000000 854.03471274 4-A-2 0.00203679 0.00000000 3.85978187 0.00000000 854.03471222 A-X 0.00261201 0.00000000 4.92981010 0.00000000 874.08285117 PO 0.00000000 0.00000000 0.00000000 0.00000000 911.13136753 A-LR 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 A-UR 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 15-B-1 0.00381982 0.00000000 5.15145946 0.00000000 984.62731532 15-B-2 0.00382671 0.00000000 5.15144404 0.00000000 984.62732852 15-B-3 0.00384615 0.00000000 5.15144231 0.00000000 984.62730769 30-B-1 0.00315339 0.00000000 5.40060183 0.00000000 996.40811789 30-B-2 0.00314775 0.00000000 5.40059957 0.00000000 996.40811563 30-B-3 0.00315714 0.00000000 5.40060000 0.00000000 996.40811429 HY-B-1 0.00244151 0.00000000 4.18186729 0.00000000 995.81877074 HY-B-2 0.00244306 0.00000000 4.18186335 0.00000000 995.81877847 HY-B-3 0.00243094 0.00000000 4.18187845 0.00000000 995.81878453 15-B-4 0.00381295 0.00000000 5.15143885 0.00000000 984.62733813 15-B-5 0.00376812 0.00000000 5.15144928 0.00000000 984.62724638 15-B-6 0.00379562 0.00000000 5.15144121 0.00000000 984.62731795 C-B-4 0.00301020 0.00000000 5.15170068 0.00000000 996.28722789 C-B-5 0.00299320 0.00000000 5.15170068 0.00000000 996.28721088 C-B-6 0.00301060 0.00000000 5.15170529 0.00000000 996.29280648 (6) Amount Does Not Include Excess Special Hazard, ~~2004~~Bankruptcy,or ~~providing~~Fraud ~~for~~Losses Unless Otherwise Disclosed. Please Refer to the ~~issuance~~Prospectus ofSupplement for a Full Description.

~~MASTR~~Certificateholder ~~Seasoned~~Component ~~Securitization~~Statement ~~Trust~~Component ~~2004~~Beginning Ending Beginning Ending Ending Pass-Through Notional Notional Component Component Component Class Rate Balance Balance Balance Balance Percentage A-X-1 6.50000% 199,133.51 191,984.94 0.00 0.00 89.97667453% A-X-2 6.50000% 19,926,771.99 19,126,804.01 0.00 0.00 87.38324803%

~~Mortgage~~CERTIFICATEHOLDER ~~Pass-Through~~ACCOUNT ~~Certificates~~STATEMENT CERTIFICATE ACCOUNT Beginning Balance 0.00 Deposits Payments of Interest and Principal 29,300,685.76 ~~Series~~Liquidations, ~~2004-1~~Insurance Proceeds, Reserve Funds 0.00 Proceeds from Repurchased Loans 0.00 Other Amounts (Servicer Advances) 179,269.69 Realized Loss (Gains, Subsequent Expenses & Recoveries) 0.00 Prepayment Penalties 0.00 Total Deposits 29,479,955.45 Withdrawals Reimbursement for Servicer Advances 0.00 Payment of Service Fee 145,234.71 Payment of Interest and Principal 29,334,720.74 Total Withdrawals (Pool Distribution Amount) 29,479,955.45 Ending Balance 0.00

~~Mortgage~~PREPAYMENT/CURTAILMENT ~~Asset~~INTEREST ~~Securitization~~SHORTFALL ~~Transactions~~Total Prepayment/Curtailment Interest Shortfall 2,004.41 ~~Inc~~Servicing Fee Support 0.00 Non-Supported Prepayment/Curtailment Interest Shortfall 2,004.41

~~(Exact~~SERVICING ~~name~~FEES ofGross ~~registrant~~Servicing asFee ~~specified~~145,122.06 inLPMI ~~its~~112.65 ~~charter)~~Supported Prepayment/Curtailment Interest Shortfall 0.00 Net Servicing Fee 145,234.71

Delaware	333-106982-45	06-1204982
(State or Other Jurisdiction of Incorporation)	(Commission File Number)	(I.R.S. Employer Identification Number)
1285 Avenue of the Americas New York, New York	10019

~~Registrant’s~~Delinquency ~~telephone~~Status ~~number~~By Groups DELINQUENT BANKRUPTCY FORECLOSURE REO Total 1 No of Loans No of Loans No of Loans No of Loans No of Loans Principal Balance Principal Balance Principal Balance Principal Balance Principal Balance 0-29 Days 0 0 0 0 0.00 0.00 0.00 0.00 30 Days 1 0 0 0 1 552,144.94 ~~including~~0.00 ~~area~~0.00 ~~code:~~0.00 ~~(212)~~552,144.94 ~~713~~60 Days 2 0 0 0 2 866,754.95 0.00 0.00 0.00 866,754.95 90 Days 0 0 0 0 0 0.00 0.00 0.00 0.00 0.00 120 Days 0 0 0 0 0 0.00 0.00 0.00 0.00 0.00 150 Days 1 0 0 0 1 687,527.81 0.00 0.00 0.00 687,527.81 180 Days 0 0 0 0 0 0.00 0.00 0.00 0.00 0.00 Totals 4 0 0 0 4 2,106,427.70 0.00 0.00 0.00 2,106,427.70 0-~~2000~~29 Days 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 30 Days 0.309598% 0.000000% 0.000000% 0.000000% 0.309598% 0.440563% 0.000000% 0.000000% 0.000000% 0.440563% 60 Days 0.619195% 0.000000% 0.000000% 0.000000% 0.619195% 0.691593% 0.000000% 0.000000% 0.000000% 0.691593% 90 Days 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 120 Days 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 150 Days 0.309598% 0.000000% 0.000000% 0.000000% 0.309598% 0.548586% 0.000000% 0.000000% 0.000000% 0.548586% 180 Days 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% Totals 1.238390% 0.000000% 0.000000% 0.000000% 1.238390% 1.680742% 0.000000% 0.000000% 0.000000% 1.680742% DELINQUENT BANKRUPTCY FORECLOSURE REO Total 2 No of Loans No of Loans No of Loans No of Loans No of Loans Principal Balance Principal Balance Principal Balance Principal Balance Principal Balance 0-29 Days 1 0 0 1 354,085.00 0.00 0.00 354,085.00 30 Days 39 0 0 0 39 16,623,454.37 0.00 0.00 0.00 16,623,454.37 60 Days 8 0 0 0 8 3,564,418.24 0.00 0.00 0.00 3,564,418.24 90 Days 0 0 0 0 0 0.00 0.00 0.00 0.00 0.00 120 Days 0 0 0 0 0 0.00 0.00 0.00 0.00 0.00 150 Days 1 0 0 0 1 666,880.01 0.00 0.00 0.00 666,880.01 180 Days 0 0 0 0 0 0.00 0.00 0.00 0.00 0.00 Totals 48 1 0 0 49 20,854,752.62 354,085.00 0.00 0.00 21,208,837.62 0-29 Days 0.102041% 0.000000% 0.000000% 0.102041% 0.086314% 0.000000% 0.000000% 0.086314% 30 Days 3.979592% 0.000000% 0.000000% 0.000000% 3.979592% 4.052250% 0.000000% 0.000000% 0.000000% 4.052250% 60 Days 0.816327% 0.000000% 0.000000% 0.000000% 0.816327% 0.868888% 0.000000% 0.000000% 0.000000% 0.868888% 90 Days 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 120 Days 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 150 Days 0.102041% 0.000000% 0.000000% 0.000000% 0.102041% 0.162563% 0.000000% 0.000000% 0.000000% 0.162563% 180 Days 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% Totals 4.897959% 0.102041% 0.000000% 0.000000% 5.000000% 5.083701% 0.086314% 0.000000% 0.000000% 5.170015% DELINQUENT BANKRUPTCY FORECLOSURE REO Total 3 No of Loans No of Loans No of Loans No of Loans No of Loans Principal Balance Principal Balance Principal Balance Principal Balance Principal Balance 0-29 Days 0 0 0 0 0.00 0.00 0.00 0.00 30 Days 0 0 0 0 0 0.00 0.00 0.00 0.00 0.00 60 Days 0 0 0 0 0 0.00 0.00 0.00 0.00 0.00 90 Days 0 0 0 0 0 0.00 0.00 0.00 0.00 0.00 120 Days 0 0 0 0 0 0.00 0.00 0.00 0.00 0.00 150 Days 0 0 0 0 0 0.00 0.00 0.00 0.00 0.00 180 Days 0 0 0 0 0 0.00 0.00 0.00 0.00 0.00 Totals 0 0 0 0 0 0.00 0.00 0.00 0.00 0.00 0-29 Days 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 30 Days 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 60 Days 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 90 Days 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 120 Days 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 150 Days 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 180 Days 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% Totals 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% DELINQUENT BANKRUPTCY FORECLOSURE REO Total 4 No of Loans No of Loans No of Loans No of Loans No of Loans Principal Balance Principal Balance Principal Balance Principal Balance Principal Balance 0-29 Days 0 0 0 0 0.00 0.00 0.00 0.00 30 Days 3 0 0 0 3 1,852,961.16 0.00 0.00 0.00 1,852,961.16 60 Days 0 0 0 0 0 0.00 0.00 0.00 0.00 0.00 90 Days 0 0 0 0 0 0.00 0.00 0.00 0.00 0.00 120 Days 0 0 0 0 0 0.00 0.00 0.00 0.00 0.00 150 Days 0 0 0 0 0 0.00 0.00 0.00 0.00 0.00 180 Days 0 0 0 0 0 0.00 0.00 0.00 0.00 0.00 Totals 3 0 0 0 3 1,852,961.16 0.00 0.00 0.00 1,852,961.16 0-29 Days 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 30 Days 2.054795% 0.000000% 0.000000% 0.000000% 2.054795% 2.756577% 0.000000% 0.000000% 0.000000% 2.756577% 60 Days 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 90 Days 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 120 Days 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 150 Days 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 180 Days 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% 0.000000% Totals 2.054795% 0.000000% 0.000000% 0.000000% 2.054795% 2.756577% 0.000000% 0.000000% 0.000000% 2.756577%

~~Check~~OTHER ~~the~~INFORMATION ~~appropriate~~Current ~~box~~Period ~~below~~Class ifA ~~the~~Insufficient ~~Form~~Funds ~~8-K~~0.00 ~~filing~~Principal isBalance ~~intended to simultaneously satisfy the filing obligation~~ of ~~the~~Contaminated ~~registrant~~Properties ~~under~~0.00 ~~any~~Periodic ofAdvance ~~the following provisions (see General Instruction A~~179,269.~~2. below):~~69

[COLLATERAL ~~] Written~~STATEMENT ~~communications~~Collateral ~~pursuant~~Description toMixed ~~Rule~~Fixed ~~425~~& ~~under~~Arm ~~the~~Weighted ~~Securities~~Average ~~Act~~Gross ~~(17~~Coupon ~~CFR~~6.642846% ~~230~~Weighted Average Pass-Through Rate 6.~~425~~379422% Weighted Average Maturity(Stepdown Calculation ) 284 Beginning Scheduled Collateral Loan Count 1,580 Number Of Loans Paid In Full 60 Ending Scheduled Collateral Loan Count 1,520 Beginning Scheduled Collateral Balance 661,600,588.96 Ending Scheduled Collateral Balance 635,781,054.61 Ending Actual Collateral Balance at 30-Nov-2004 636,879,188.48 Monthly P &I Constant 5,006,613.77 Special Servicing Fee 0.00 Prepayment Penalties 0.00 Realized Loss Amount 0.00 Cumulative Realized Loss 0.00 Class A Optimal Amount 29,068,210.23 Class AP Deferred Amount 0.00 Scheduled Principal 1,344,188.11 Unscheduled Principal 24,475,346.24

[Group ~~] Soliciting~~Level ~~material~~Collateral ~~pursuant~~Statement toGroup ~~Rule~~1 ~~14a-~~2 3 Collateral Description Fixed 15 Year Fixed 30 Year Ratio Strip Mixed ARM Weighted Average Coupon Rate 6.509762 6.991658 5.043006 Weighted Average Net Rate 6.259961 6.745980 4.672189 Weighted Average Maturity 143 314 331 Beginning Loan Count 335 1,019 75 Loans Paid In Full 12~~(b)~~ ~~under~~39 ~~the~~4 ~~Exchange~~Ending ~~Act~~Loan (Count 323 980 71 Beginning Scheduled Balance 129,436,781.38 426,862,242.55 35,734,055.70 Ending scheduled Balance 124,790,211.43 409,784,990.17 ~~CFR~~34,062,087.64 ~~240~~Record Date 11/30/2004 11/30/2004 11/30/2004 Principal And Interest Constant 1,381,344.~~14a~~16 3,005,069.59 200,507.41 Scheduled Principal 679,175.32 518,007.23 50,334.85 Unscheduled Principal 3,967,394.63 16,559,245.15 1,621,633.21 Scheduled Interest 702,168.84 2,487,062.36 150,172.56 Servicing Fees 26,944.54 87,392.31 11,042.35 Master Servicing Fees 0.00 0.00 0.00 Trustee Fee 0.00 0.00 0.00 FRY Amount 0.00 0.00 0.00 Special Hazard Fee 0.00 0.00 0.00 Other Fee 0.00 112.65 0.00 Pool Insurance Fee 0.00 0.00 0.00 Spread Fee 1 0.00 0.00 0.00 Spread Fee 2 0.00 0.00 0.00 Spread Fee 3 0.00 0.00 0.00 Net Interest 675,224.30 2,399,557.40 139,130.21 Realized Loss Amount 0.00 0.00 0.00 Cumulative Realized Loss 0.00 0.00 0.00 Percentage of Cumulative Losses 0.0000 0.0000 0.0000 Prepayment Penalties 0.00 0.00 0.00 Special Servicing Fee 0.00 0.00 0.00 Pass-~~12(b))~~Through Rate 6.259961 6.745663 4.672189

[Group ~~] Pre-commencement~~Level ~~communications~~Collateral ~~pursuant~~Statement toGroup ~~Rule~~4 ~~14d-~~Total Collateral Description Mixed ARM Mixed Fixed & Arm Weighted Average Coupon Rate 5.571944 6.642846 Weighted Average Net Rate 5.231391 6.379626 Weighted Average Maturity 330 284 Beginning Loan Count 151 1,580 Loans Paid In Full 5 60 Ending Loan Count 146 1,520 Beginning Scheduled Balance 69,567,509.33 661,600,588.96 Ending scheduled Balance 67,143,765.37 635,781,054.61 Record Date 11/30/2004 11/30/2004 Principal And Interest Constant 419,692.61 5,006,613.77 Scheduled Principal 96,670.71 1,344,188.11 Unscheduled Principal 2~~(b)~~,327,073.25 ~~under~~24,475,346.24 ~~the~~Scheduled ~~Exchange~~Interest ~~Act~~323,021.90 ~~(17~~3,662,425.66 ~~CFR~~Servicing ~~240~~Fees 19,742.~~14d-~~86 145,122.06 Master Servicing Fees 0.00 0.00 Trustee Fee 0.00 0.00 FRY Amount 0.00 0.00 Special Hazard Fee 0.00 0.00 Other Fee 0.00 112.65 Pool Insurance Fee 0.00 0.00 Spread Fee 1 0.00 0.00 Spread Fee 2~~(b))~~ 0.00 0.00 Spread Fee 3 0.00 0.00 Net Interest 303,279.04 3,517,190.95 Realized Loss Amount 0.00 0.00 Cumulative Realized Loss 0.00 0.00 Percentage of Cumulative Losses 0.0000 0.0000 Prepayment Penalties 0.00 0.00 Special Servicing Fee 0.00 0.00 Pass-Through Rate 5.231391 6.379422

[Miscellaneous ~~] Pre-commencement~~Reporting ~~communications~~Group ~~pursuant~~1 toSenior ~~Rule~~% ~~13e-4(c)~~98.938856% ~~under~~Senior ~~the~~Prepayment ~~Exchange~~% ~~Act~~100.000000% ~~(17~~Subordinate ~~CFR~~% ~~240~~1.~~13e-4(c))~~061144% Group 2 Senior % 97.246885% Senior Prepayment % 100.000000% Subordinate % 2.753115% Group 3 Senior % 96.753075% Senior Prepayment % 100.000000% Subordinate % 3.246925%

~~-2-~~Miscellaneous Reporting Group 4 Senior % 96.913759% Senior Prepayment % 100.000000% Subordinate % 3.086241%

Group

Item 2.01. Completion of Acquisition or Disposition of Assets

Description of the Certificates and the Mortgage Pool

On September 30, 2004, a single series of certificates, entitled MASTR Seasoned Securitization Trust 2004-1, Mortgage Pass-Through Certificates, Series 2004-1 (the “Certificates”), were issued pursuant to a pooling and servicing agreement, dated as of September 1, 2004 (the “Agreement”), attached hereto as Exhibit 4.1, among Mortgage Asset Securitization Transactions, Inc. as depositor (the “Depositor”), Wells Fargo Bank, N.A. as master servicer, trust administrator and a custodian, Wachovia Bank, National Association as trustee, and U.S. Bank National Association as a custodian. The Certificates consist of twenty-nine classes of certificates (collectively, the “Certificates”), designated as the “Class 1-A-1 Certificates”, “Class 2-A-1 Certificates”, “Class 2-A-2 Certificates”, “Class 2-A-3 Certificates”, “Class 2-A-4 Certificates”, “Class 2-A-5 Certificates”, “Class 2-A-6 Certificates”, “Class 3-A-1 Certificates”, “Class 4-A-1 Certificates”, “Class 4-A-2 Certificates”, “Class A-X Certificates”, “Class PO Certificates”, “Class A-LR Certificates”, “Class A-UR Certificates”, “Class 15-B-1 Certificates”, “Class 15-B-2 Certificates”, “Class 15-B-3 Certificates”, “Class 15-B-4 Certificates”, “Class 15-B-5 Certificates”, “Class 15-B-6 Certificates”, “Class 30-B-1 Certificates”, “Class 30-B-2 Certificates”, “Class 30-B-3 Certificates”, “Class HY-B-1 Certificates”, “Class HY-B-2 Certificates”, “Class HY-B-3 Certificates”, “Class C-B-4 Certificates”, “Class C-B-5 Certificates” and “Class C-B-6 Certificates”. The Certificates evidence in the aggregate the entire beneficial ownership interest in a trust fund (the “Trust Fund”), consisting of a pool of mortgage loans (the “Mortgage Pool’“) of conventional, one- to four- family, adjustable rate and fixed rate, first lien mortgage loans having original terms to maturity up to 30 years (the “Mortgage Loans”). The Mortgage Pool consists of Mortgage Loans having an aggregate principal balance of approximately $726,285,591 as of September 1, 2004 (the “Cut-off Date”). The Mortgage Loans were purchased pursuant to the Mortgage Loan Purchase Agreement, dated September 30, 2004, between UBS Real Estate Securities Inc. (“UBSRES”), and the Depositor (the “Mortgage Loan Purchase Agreement”). The Class 1-A-1 Certificates, Class 2-A-1 Certificates, Class 2-A-2 Certificates, Class 2-A-3 Certificates, Class 2-A-4 Certificates, Class 2-A-5 Certificates, Class 2-A-6 Certificates, Class 3-A-1 Certificates, Class 4-A-1 Certificates, Class 4-A-2 Certificates, Class A-X Certificates, Class PO Certificates, Class A-LR Certificates, Class A-UR Certificates, Class 15-B-1 Certificates, Class 15-B-2 Certificates, Class 15-B-3 Certificates, Class 30-B-1 Certificates, Class 30-B-2 Certificates, Class 30-B-3 Certificates, Class HY-B-1 Certificates, Class HY-B-2 Certificates and Class HY-B-3 Certificates, were sold by the Depositor to UBS Securities LLC (the “Underwriter”), pursuant to an Underwriting Agreement, dated September 30, 2004 (the “Underwriting Agreement”) between the Depositor and the Underwriter.

The Certificates have the following initial Certificate Balances and Pass-Through Rates:

-3-

	Initial Class Principal Balance or Notional Amount		Initial Pass-Through Rate
Class 1-A-1	$	137,304,000		Variable
Class 2-A-1	$	202,458,499		8.0000%
Class 2-A-2	$	50,000,000		5.5000%
Class 2-A-3	$	50,000,000		5.2500%
Class 2-A-4	$	127,458,501		5.0000%
Class 2-A-5	$	20,927,000		6.5000%
Class 2-A-6	$	500,000		6.5000%
Class 3-A-1	$	41,159,000		Variable
Class 4-A-1	$	72,304,000		Variable
Class 4-A-2	$	3,805,000		Variable
Class A-X		Notional Amount		6.5000%
Class PO	$	3,989,934		N/A
Class A-LR	$	50		Variable
Class A-UR	$	50		Variable
Class 15-B-1	$	555,000		Variable
Class 15-B-2	$	277,000		Variable
Class 15-B-3	$	208,000		Variable
Class 30-B-1	$	8,873,000		6.5000%
Class 30-B-2	$	934,000		6.5000%
Class 30-B-3	$	700,000		6.5000%
Class HY-B-1	$	2,351,000		Variable
Class HY-B-2	$	483,000		Variable
Class HY-B-3	$	181,000		Variable
Class 15-B-4	$	139,000		Variable
Class 15-B-5	$	69,000		Variable
Class 15-B-6	$	139,634		Variable
Class C-B-4	$	588,000		Variable
Class C-B-5	$	294,000		Variable
Class C-B-6	$	587,921		Variable

The Certificates, other than the Class 15-B-4 Certificates, Class 15-B-5 Certificates, Class 15-B-6 Certificates, Class C-B-4 Certificates, Class C-B-5 Certificates and Class C-B-6 Certificates (together, the “Private Certificates”), and the Mortgage Loans are more particularly described in the Prospectus, dated September 30, 2004 and the Prospectus Supplement, dated September 30, 2004, as previously filed with the Securities and Exchange Commission pursuant to Rule 424(b). The Private Certificates have not been and will not be publicly offered by the Depositor. Capitalized terms used but not otherwise defined herein shall have the meanings assigned to them in the Prospectus Supplement.

Item 9.01. Financial Statements and Exhibits

(a) Not applicable

(b) Not applicable

-4-

Exhibit No.		Description
4.1		Pooling and Servicing Agreement, dated as of September 1, 2004, by and among Mortgage Asset Securitization Transactions, Inc. as depositor (the “Depositor”), Wells Fargo Bank, N.A. as master servicer, trust administrator and a custodian, Wachovia Bank, National Association as trustee and U.S. Bank National Association as a custodian, relating to the MASTR Seasoned Securitization Trust 2004-1, Mortgage Pass-Through Certificates, Series 2004-1.

-5-

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 thereunto duly authorized.

Dated: September 30, 2004

MORTGAGE ASSET SECURITIZATION TRANSACTIONS, INC. By: /s/ Peter Ma Name: Peter Ma Title: Director By: /s/ Hugh Corcoran Name: Hugh Corcoran Title: Managing Director

-6-

Index to Exhibits

Exhibit No.		Description		Sequentially Numbered Page
4.1		Pooling and Servicing Agreement, dated as of September 1, 2004, by and among Mortgage Asset Securitization Transactions, Inc. as depositor (the “Depositor”), Wells Fargo Bank, N.A. as master servicer, trust administrator and a custodian, Wachovia Bank, National Association as trustee and U.S. Bank National Association as a custodian, relating to the MASTR Seasoned Securitization Trust 2004-1, Mortgage Pass-Through Certificates, Series 2004-1.		7

-7-

Filing Compare · MASTR Seasoned Securitization Trust 2004-1