Structured  Asset Securities Corporation  Mortgage Pass-Through Certificates,  Series
2004-S1
Distribution Date:     05/25/2004
Record Date:           04/30/2004

Distribution Summary

DISTRIBUTION IN DOLLARS

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

A1                     157,734,000.00        148,514,919.021.230000%       147,153.53  6,522,648.02    6,669,801.55   0.00                   0.00        141,992,271.00

A2                     18,486,000.00         18,486,000.00 1.450000%       21,592.68   0.00            21,592.68      0.00                   0.00        18,486,000.00

M1                     23,285,000.00         23,285,000.00 1.650000%       30,949.65   0.00            30,949.65      0.00                   0.00        23,285,000.00

M2                     19,509,000.00         19,509,000.00 2.250000%       35,360.06   0.00            35,360.06      0.00                   0.00        19,509,000.00

M3                     11,328,000.00         11,328,000.00 2.600000%       23,725.87   0.00            23,725.87      0.00                   0.00        11,328,000.00

M4                     6,922,000.00          6,922,000.00  2.800000%       15,612.96   0.00            15,612.96      0.00                   0.00        6,922,000.00

M5                     3,650,000.00          3,650,000.00  3.850000%       11,320.07   0.00            11,320.07      0.00                   0.00        3,650,000.00

B1                     6,419,000.00          6,419,000.00  7.000000%       37,444.17   0.00            37,444.17      0.00                   0.00        6,419,000.00

B2                     4,405,000.00          4,405,000.00  7.000000%       25,695.83   0.00            25,695.83      0.00                   0.00        4,405,000.00

X                      221.66                221.66        0.000000%       1,670,740.890.00            1,670,740.89   0.00                   0.00        221.66

P                      100.00                100.00        0.000000%       45,330.28   0.00            45,330.28      0.00                   0.00        100.00

R                      0.00                  0.00          0.000000%       0.00        0.00            0.00           0.00                   0.00        0.00

Totals                 251,738,321.66        242,519,240.68                2,064,925.996,522,648.02    8,587,574.01   0.00                   0.00        225,172,271.00

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)    Distributed Distributed     Interest       Loss                   Balance
                                             (3/2 x 1000)                  (6/2 x 1000)(7/2 x 1000)    (8/2 x 1000)   (9/2 x 1000)           (10/2 x
                                                                                                                                             1000)

A1                     86359BKR1             941.552988    0.932922        41.352201   42.285123       0.000000       0.000000               900.200787

A2                     86359BKS9             1,000.000000  1.168056        0.000000    1.168056        0.000000       0.000000               1,000.000000

M1                     86359BKT7             1,000.000000  1.329167        0.000000    1.329167        0.000000       0.000000               1,000.000000

M2                     86359BKU4             1,000.000000  1.812500        0.000000    1.812500        0.000000       0.000000               1,000.000000

M3                     86359BKV2             1,000.000000  2.094445        0.000000    2.094445        0.000000       0.000000               1,000.000000

M4                     86359BKW0             1,000.000000  2.255556        0.000000    2.255556        0.000000       0.000000               1,000.000000

M5                     86359BKX8             1,000.000000  3.101389        0.000000    3.101389        0.000000       0.000000               1,000.000000

B1                     86359BLY5             1,000.000000  5.833334        0.000000    5.833334        0.000000       0.000000               1,000.000000

B2                     86359BLZ2             1,000.000000  5.833333        0.000000    5.833333        0.000000       0.000000               1,000.000000

X                                            1,000.000000  7,537,403.6362000.000000    7,537,403.6362000.000000       0.000000               1,000.000000

P                                            1,000.000000  453,302.800000  0.000000    453,302.800000  0.000000       0.000000               1,000.000000

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)

A1                     148,514,919.02        1.230000%     147,153.53      0.00        0.00            147,153.53     0.00                   147,153.53  0.00

A2                     18,486,000.00         1.450000%     21,592.68       0.00        0.00            21,592.68      0.00                   21,592.68   0.00

M1                     23,285,000.00         1.650000%     30,949.65       0.00        0.00            30,949.65      0.00                   30,949.65   0.00

M2                     19,509,000.00         2.250000%     35,360.06       0.00        0.00            35,360.06      0.00                   35,360.06   0.00

M3                     11,328,000.00         2.600000%     23,725.87       0.00        0.00            23,725.87      0.00                   23,725.87   0.00

M4                     6,922,000.00          2.800000%     15,612.96       0.00        0.00            15,612.96      0.00                   15,612.96   0.00

M5                     3,650,000.00          3.850000%     11,320.07       0.00        0.00            11,320.07      0.00                   11,320.07   0.00

B1                     6,419,000.00          7.000000%     37,444.17       0.00        0.00            37,444.17      0.00                   37,444.17   0.00

B2                     4,405,000.00          7.000000%     25,695.83       0.00        0.00            25,695.83      0.00                   25,695.83   0.00

X                      221.66                0.000000%     1,670,740.89    0.00        0.00            1,670,740.89   0.00                   1,670,740.890.00

P                      100.00                0.000000%     45,330.28       0.00        0.00            45,330.28      0.00                   45,330.28   0.00

R                      0.00                  0.000000%     0.00            0.00        0.00            0.00           0.00                   0.00        0.00

  Totals               242,519,240.68                      2,064,925.99    0.00        0.00            2,064,925.99   0.00                   2,064,925.990.00

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)

A1                     157,734,000.00        148,514,919.026,522,648.02    0.00        0.00            0.00           141,992,271.00         0.00

A2                     18,486,000.00         18,486,000.00 0.00            0.00        0.00            0.00           18,486,000.00          0.00

M1                     23,285,000.00         23,285,000.00 0.00            0.00        0.00            0.00           23,285,000.00          0.00

M2                     19,509,000.00         19,509,000.00 0.00            0.00        0.00            0.00           19,509,000.00          0.00

M3                     11,328,000.00         11,328,000.00 0.00            0.00        0.00            0.00           11,328,000.00          0.00

M4                     6,922,000.00          6,922,000.00  0.00            0.00        0.00            0.00           6,922,000.00           0.00

M5                     3,650,000.00          3,650,000.00  0.00            0.00        0.00            0.00           3,650,000.00           0.00

B1                     6,419,000.00          6,419,000.00  0.00            0.00        0.00            0.00           6,419,000.00           0.00

B2                     4,405,000.00          4,405,000.00  0.00            0.00        0.00            0.00           4,405,000.00           0.00

X                      221.66                221.66        0.00            0.00        0.00            0.00           221.66                 0.00

P                      100.00                100.00        0.00            0.00        0.00            0.00           100.00                 0.00

R                      0.00                  0.00          0.00            0.00        0.00            0.00           0.00                   0.00

  Totals               247,333,000.00        242,519,240.686,522,648.02    323,158.99  6,522,648.02    0.00           235,996,592.66         0.00

Collateral Summary

ASSET CHARACTERISTICS

                       Cut-Off               Prior         Current

Aggregate Stated
Principal Balance      251,738,321.66        242,519,240.68235,996,592.66

Loan Count             6,184                 5,992         5,861

Weighted Average Coupon
Rate (WAC)             10.522611%            10.520469%    N/A

Net Weighted Average
Coupon Rate (Net WAC)  10.172207%            10.008969%    N/A

Weighted Average
Maturity (WAM in       209                   208           207
months)

AVAILABLE PRINCIPAL    AVAILABLE INTEREST

Scheduled Interest     2,126,180.26
Curtailments           101,406.31
Less:                  Servicing Fees        101,050.00
Insurance Fees         0.00
Uncompensated PPIS     0.00
Trustee Fees           2,324.09
Credit Manager Fees    3,031.49
Relief Act Shortfall   178.99
Other Interest
Reductions             0.00
Current Realized Losses0.00
TOTAL AVAILABLE
INTEREST               2,019,595.69

Delinquency Information

                       30-59 Days            60-89 Days    90+ Days        Totals

Delinquency

Scheduled Principal
Balance                3,150,170.06          290,790.97    278,881.79      3,719,842.82
Percentage of Total
Pool Balance           1.3348%               0.1232%       0.1182%         1.5762%
Number of Loans        73                    5             8               86

Percentage of Total
Loans                  1.2455%               0.0853%       0.1365%         1.4673%
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                                      3,150,170.06  290,790.97      278,881.79  3,719,842.82
Percentage of Total Pool Balance             1.3348%       0.1232%         0.1182%     1.5762%

Number of Loans                              73            5               8           86
Percentage of Total
Loans                                        1.2455%       0.0853%         0.1365%     1.4673%

Principal and Interest
Advances               1,557,054.42

Credit Enhancement

GROUP 1

Required Overcollateralization Amount        0.00
Prior Overcollateralization Amount           321.66        0.0001%
Overcollateralization
Deficiency Amount      0.00
Excess
Overcollateralization  0.00
Amount

Excess Spread Available
for O/C Deficiency     0.00
Overcollateralization
Increase Amount        0.00
Overcollateralization
Reduction Amount       0.00

Current
Overcollateralization                        321.66        0.0001%

Other Information

Class X Notional Amount235,996,592.66

Current Libor          1.100000%
Next Libor             1.100000%

Basis Risk Reserve Fund
Balance                1,000.00

A1 Next Pass-Through
Rate                   1.230000%
A2 Next Pass-Through
Rate                   1.450000%
M1 Next Pass-Through
Rate                   1.650000%
M2 Next Pass-Through
Rate                   2.250000%
M3 Next Pass-Through
Rate                   2.600000%
M4 Next Pass-Through
Rate                   2.800000%
M5 Next Pass-Through
Rate                   3.850000%
B1 Next Pass-Through
Rate                   7.000000%
B2 Next Pass-Through
Rate                   7.000000%

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     2
2530 South Parker Road, Suite 601

Delinquency Information2

Trustee                Citibank, N.A.
Credit Enhancement     2

New York, NY  10005
Other Information      2

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 SEC CORP MORT PASS THR CERTS SER 2004-S1 8-K