Structured Asset Securities Corporation  Mortgage Pass-Through Certificates, Series
2004-12H
Distribution Date:     09/27/2004
Record Date:           08/31/2004

Distribution Summary

DISTRIBUTION IN DOLLARS

                                             Prior         Pass-                                                                                  Current
                       Original              Principal     Through       Interest   Principal   Total          Deferred               Realized    Principal
Class                  Balance               Balance       Rate          DistributedDistributed Distributed    Interest               Loss        Balance
(1)                    (2)                   (3)           (4)           (5)        (6)         (7)=(5+6)      (8)                    (9)         (10)=(3-6+8-9)

A1I                    137,933,000.00        131,648,302.286.000000%     658,241.51 3,082,156.493,740,398.00   0.00                   0.00        128,566,145.79

APOI                   4,239,312.00          4,133,507.02  0.000000%     0.00       96,509.54   96,509.54      0.00                   0.00        4,036,997.48

A1II                   26,365,000.00         24,893,537.71 5.597710%     116,122.33 574,917.62  691,039.95     0.00                   0.00        24,318,620.09

B1I                    1,393,000.00          1,388,956.59  6.000000%     6,944.78   1,366.69    8,311.47       0.00                   0.00        1,387,589.90

B2I                    1,173,000.00          1,169,595.18  6.000000%     5,847.98   1,150.84    6,998.82       0.00                   0.00        1,168,444.34

B1II                   258,000.00            257,256.44    5.597710%     1,200.04   250.49      1,450.53       0.00                   0.00        257,005.95

B2II                   218,000.00            217,371.72    5.597710%     1,013.99   211.66      1,225.65       0.00                   0.00        217,160.06

B3                     956,000.00            953,228.15    5.937023%     4,716.11   936.41      5,652.52       0.00                   0.00        952,291.74

B4                     522,000.00            520,486.50    5.937023%     2,575.12   511.31      3,086.43       0.00                   0.00        519,975.19

B5                     261,000.00            260,243.26    5.937023%     1,287.56   255.65      1,543.21       0.00                   0.00        259,987.61

B6                     522,009.00            520,495.84    5.937023%     2,575.16   511.32      3,086.48       0.00                   0.00        519,984.52

R                      100.00                0.00          6.000000%     0.00       0.00        0.00           0.00                   0.00        0.00

Totals                 173,840,421.00        165,962,980.69              800,524.58 3,758,778.024,559,302.60   0.00                   0.00        159,951,963.61

Notional Classes

AIOI                   26,435,000.00         24,375,768.81 1.000000%     20,313.14  0.00        20,313.14      0.00                   0.00        23,646,599.49

Distribution Summary (Factors)

PER $1,000 OF ORIGINAL BALANCE

                                             Prior                                                                                    Current
                                             Principal     Interest      Principal  Total       Deferred       Realized               Principal
                                                           Distributed
Class                  CUSIP                 Balance       (5/2 x 1000)  DistributedDistributed Interest       Loss                   Balance
                                             (3/2 x 1000)                (6/2 x     (7/2 x 1000)(8/2 x 1000)   (9/2 x 1000)           (10/2 x
                                                                         1000)                                                        1000)

A1I                    86359BUP4             954.436591    4.772183      22.345316  27.117499   0.000000       0.000000               932.091275

APOI                   86359BUR0             975.041945    0.000000      22.765378  22.765378   0.000000       0.000000               952.276568

A1II                   86359BUS8             944.188800    4.404412      21.806092  26.210504   0.000000       0.000000               922.382708

B1I                    86359BUT6             997.097337    4.985485      0.981113   5.966597    0.000000       0.000000               996.116224

B2I                    86359BUU3             997.097340    4.985490      0.981108   5.966598    0.000000       0.000000               996.116232

B1II                   86359BUV1             997.117984    4.651318      0.970891   5.622209    0.000000       0.000000               996.147093

B2II                   86359BUW9             997.117982    4.651330      0.970917   5.622248    0.000000       0.000000               996.147064

B3                     86359BUX7             997.100575    4.933169      0.979508   5.912678    0.000000       0.000000               996.121067

B4                     86359BUZ2             997.100575    4.933180      0.979521   5.912701    0.000000       0.000000               996.121054

B5                     86359BVA6             997.100613    4.933180      0.979502   5.912682    0.000000       0.000000               996.121111

B6                     86359BVB4             997.101276    4.933172      0.979523   5.912695    0.000000       0.000000               996.121753

R                      86359BUY5             0.000000      0.000000      0.000000   0.000000    0.000000       0.000000               0.000000

AIOI                   86359BUQ2             922.102092    0.768418      0.000000   0.768418    0.000000       0.000000               894.518611

Interest Distribution
Detail

DISTRIBUTION IN DOLLARS

                       Prior                 Pass-         Optimal       Prior      Non-Recov                                                     Current
                       Principal             Through       Accrued       Unpaid     Interest    Interest       Deferred               Interest    Unpaid
                                                                                                                                      Distributed
Class                  Balance               Rate          Interest      Interest   Shortfall   Due            Interest               (9)         Interest
(1)                    (2)                   (3)           (4)           (5)        (6)         (7)=(4)+(5)-(6)(8)                                (10)=(7)-(8)-(9)

A1I                    131,648,302.28        6.000000%     658,241.51    0.00       0.00        658,241.51     0.00                   658,241.51  0.00

APOI                   4,133,507.02          0.000000%     0.00          0.00       0.00        0.00           0.00                   0.00        0.00

A1II                   24,893,537.71         5.597710%     116,122.33    0.00       0.00        116,122.33     0.00                   116,122.33  0.00

B1I                    1,388,956.59          6.000000%     6,944.78      0.00       0.00        6,944.78       0.00                   6,944.78    0.00

B2I                    1,169,595.18          6.000000%     5,847.98      0.00       0.00        5,847.98       0.00                   5,847.98    0.00

B1II                   257,256.44            5.597710%     1,200.04      0.00       0.00        1,200.04       0.00                   1,200.04    0.00

B2II                   217,371.72            5.597710%     1,013.99      0.00       0.00        1,013.99       0.00                   1,013.99    0.00

B3                     953,228.15            5.937023%     4,716.11      0.00       0.00        4,716.11       0.00                   4,716.11    0.00

B4                     520,486.50            5.937023%     2,575.12      0.00       0.00        2,575.12       0.00                   2,575.12    0.00

B5                     260,243.26            5.937023%     1,287.56      0.00       0.00        1,287.56       0.00                   1,287.56    0.00

B6                     520,495.84            5.937023%     2,575.16      0.00       0.00        2,575.16       0.00                   2,575.16    0.00

R                      0.00                  6.000000%     0.00          0.00       0.00        0.00           0.00                   0.00        0.00

  Totals               165,962,980.69                      800,524.58    0.00       0.00        800,524.58     0.00                   800,524.58  0.00

Notional Classes

AIOI                   24,375,768.81         1.000000%     20,313.14     0.00       0.00        20,313.14      0.00                   20,313.14   0.00

Principal Distribution
Detail

DISTRIBUTION IN DOLLARS

                                             Prior                                  Current     Current        Current                Cumulative
                       Original              Principal     Principal     Accreted   Realized    Principal      Principal              Realized
Class                  Balance               Balance       Distribution  Principal  Losses      Recoveries     Balance                Losses
(1)                    (2)                   (3)           (4)           (5)        (6)         (7)            (8)=(3)-(4)+(5)-(6)+(7)(9)

A1I                    137,933,000.00        131,648,302.283,082,156.49  0.00       0.00        0.00           128,566,145.79         0.00

APOI                   4,239,312.00          4,133,507.02  96,509.54     0.00       0.00        0.00           4,036,997.48           0.00

A1II                   26,365,000.00         24,893,537.71 574,917.62    0.00       0.00        0.00           24,318,620.09          0.00

B1I                    1,393,000.00          1,388,956.59  1,366.69      0.00       0.00        0.00           1,387,589.90           0.00

B2I                    1,173,000.00          1,169,595.18  1,150.84      0.00       0.00        0.00           1,168,444.34           0.00

B1II                   258,000.00            257,256.44    250.49        0.00       0.00        0.00           257,005.95             0.00

B2II                   218,000.00            217,371.72    211.66        0.00       0.00        0.00           217,160.06             0.00

B3                     956,000.00            953,228.15    936.41        0.00       0.00        0.00           952,291.74             0.00

B4                     522,000.00            520,486.50    511.31        0.00       0.00        0.00           519,975.19             0.00

B5                     261,000.00            260,243.26    255.65        0.00       0.00        0.00           259,987.61             0.00

B6                     522,009.00            520,495.84    511.32        0.00       0.00        0.00           519,984.52             0.00

R                      100.00                0.00          0.00          0.00       0.00        0.00           0.00                   0.00

  Totals               172,535,312.00        165,962,980.693,758,778.02  794,086.74 3,757,499.740.00           162,204,202.67         0.00

Collateral Summary -
Group 1

ASSET CHARACTERISTICS

                       Cut-Off               Prior         Current

Aggregate Stated
Principal Balance      146,645,475.89        140,241,889.41137,058,834.81

Loan Count             1,173                 1,128         1,108

Weighted Average Coupon
Rate (WAC)             6.618741%             6.604182%     N/A

Net Weighted Average
Coupon Rate (Net WAC)  6.362241%             5.996968%     N/A

Weighted Average
Maturity (WAM in       0                     349           348
months)

AVAILABLE PRINCIPAL    AVAILABLE INTEREST

PO Principal           Total Principal
Scheduled Interest     771,819.23
541.74                 19,608.56
Less:                  Master Servicing Fees 0.00
Sub Servicing Fees     29,217.06
Trustee Fees           759.59
Insurance Fees         40,987.39
Uncompensated PPIS     0.00
Relief Act Shortfall   0.00
Other Interest
Reductions             0.00
0.00                   0.00
TOTAL AVAILABLE
INTEREST               700,855.19

Collateral Summary -
Group 2

ASSET CHARACTERISTICS

                       Cut-Off               Prior         Current

Aggregate Stated
Principal Balance      27,194,946.05         25,721,091.85 25,145,368.43

Loan Count             155                   149           146

Weighted Average Coupon
Rate (WAC)             6.529476%             6.547184%     N/A

Net Weighted Average
Coupon Rate (Net WAC)  6.147976%             5.597710%     N/A

Weighted Average
Maturity (WAM in       0                     350           349
months)

AVAILABLE PRINCIPAL    AVAILABLE INTEREST

Scheduled Interest     140,333.97
Curtailments           5,344.27
Less:                  Master Servicing Fees 0.00
Sub Servicing Fees     8,037.79
Insurance Fees         12,174.07
Trustee Fees           139.35
Uncompensated PPIS     0.00
Relief Act Shortfall   0.00
Other Interest
Reductions             0.00
Current Realized Losses0.00
TOTAL AVAILABLE
INTEREST               119,982.76

Delinquency Information

 GROUP 1

Less Than
1 Month                1 Month               2 Months      3+ Months     Totals

Delinquency

Scheduled Principal
Balance                79,020.07             0.00          0.00          79,020.07
Percentage of Total
Pool Balance           0.0577%               0.0000%       0.0000%       0.0577%
Number of Loans        1                     0             0             1

Percentage of Total
Loans                  0.0903%               0.0000%       0.0000%       0.0903%
Bankruptcy

Scheduled Principal
Balance                153,515.27            0.00          0.00          0.00       153,515.27
Percentage of Total
Pool Balance           0.1120%               0.0000%       0.0000%       0.0000%    0.1120%

Number of Loans        1                     0             0             0          1
Percentage of Total
Loans                  0.0903%               0.0000%       0.0000%       0.0000%    0.0903%

Foreclosure

Scheduled Principal
Balance                                      0.00          0.00          0.00       0.00
Percentage of Total Pool Balance             0.0000%       0.0000%       0.0000%    0.0000%

Number of Loans                              0             0             0          0
Percentage of Total
Loans                                        0.0000%       0.0000%       0.0000%    0.0000%

REO

Scheduled Principal
Balance                                      0.00          0.00          0.00       0.00
Percentage of Total Pool Balance             0.0000%       0.0000%       0.0000%    0.0000%

Number of Loans                              0             0             0          0
Percentage of Total
Loans                                        0.0000%       0.0000%       0.0000%    0.0000%

Total

Scheduled Principal
Balance                153,515.27            79,020.07     0.00          0.00       232,535.34
Percentage of Total
Pool Balance           0.1120%               0.0577%       0.0000%       0.0000%    0.1697%

Number of Loans        1                     1             0             0          2
Percentage of Total
Loans                  0.0903%               0.0903%       0.0000%       0.0000%    0.1805%

Principal and Interest
Advances               528,054.54

Delinquency Information

 GROUP 2

                       1 Month               2 Months      3+ Months     Totals

Delinquency

Scheduled Principal
Balance                0.00                  0.00          0.00          0.00
Percentage of Total
Pool Balance           0.0000%               0.0000%       0.0000%       0.0000%
Number of Loans        0                     0             0             0

Percentage of Total
Loans                  0.0000%               0.0000%       0.0000%       0.0000%
Bankruptcy

Scheduled Principal
Balance                                      0.00          0.00          0.00       0.00
Percentage of Total Pool Balance             0.0000%       0.0000%       0.0000%    0.0000%

Number of Loans                              0             0             0          0
Percentage of Total
Loans                                        0.0000%       0.0000%       0.0000%    0.0000%

Foreclosure

Scheduled Principal
Balance                                      0.00          0.00          0.00       0.00
Percentage of Total Pool Balance             0.0000%       0.0000%       0.0000%    0.0000%

Number of Loans                              0             0             0          0
Percentage of Total
Loans                                        0.0000%       0.0000%       0.0000%    0.0000%

REO

Scheduled Principal
Balance                                      0.00          0.00          0.00       0.00
Percentage of Total Pool Balance             0.0000%       0.0000%       0.0000%    0.0000%

Number of Loans                              0             0             0          0
Percentage of Total
Loans                                        0.0000%       0.0000%       0.0000%    0.0000%

Total

Scheduled Principal
Balance                                      0.00          0.00          0.00       0.00
Percentage of Total Pool Balance             0.0000%       0.0000%       0.0000%    0.0000%

Number of Loans                              0             0             0          0
Percentage of Total
Loans                                        0.0000%       0.0000%       0.0000%    0.0000%

Principal and Interest
Advances               91,518.37

Other Information

          Current
Bankruptcy Loss        0.00
          Cumulative
Bankruptcy Loss        0.00
          Remaining
Bankruptcy Loss Limit  104,276.00

          Current Fraud
Loss                   0.00
          Cumulative
Fraud Loss             0.00
          Remaining
Fraud Loss Limit       3,476,808.00

          Current
Special Hazard Loss    0.00
Limit
          Cumulative
Special Hazard Loss    0.00
Limit
          Remaining
Special Hazard Loss    1,825,324.00
Limit

CONTACT INFORMATION    CONTENTS

Distribution Summary   2
Depositor              Structured Asset
                       Securities Corporation
Distribution Summary
(Factors)              2

New York, NY  10019
Interest Distribution  2
Underwriter            Lehman Brothers
745 Seventh Avenue, 7th
Floor
Principal Distribution 2
New York, NY  10019

Collateral Summary     1
2530 South Parker Road, Suite 601

Delinquency Information2

Trustee                Citibank, N.A.
Other Information      2

New York, NY  10005

Deal Contact:          Karen Schluter        Citibank, N.A.
karen.schluter@citi.com                      Agency and
                                             Trust
                                             111 Wall
Tel: (212) 657-7781                          Street, 14th
                                             Floor, Zone 3
Fax: (212) 657-4009                          New York, NY
                                             10005

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                       www.sf.citidirect.com 2004 Citigroup

Structured Asset Securities Corportion 8-K