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

                                    FORM 10-K

 X              ANNUAL REPORT PURSUANT TO SECTION 13 or 15(d) OF
---                    THE SECURITIES EXCHANGE ACT OF 1934

                      For the year ended: December 31, 1999
                                          -----------------

                                       OR

              TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF
---                    THE SECURITIES EXCHANGE ACT OF 1934

              For the Transition period from           to
                                             ---------    ---------

                         Commission file number: 33-9921
                                                 -------


                            SENIOR INCOME FUND L. P.
                            ------------------------
              Exact name of Registrant as specified in its charter


         Delaware                                                 13-3392077
         --------                                                 ----------
State or other jurisdiction of                                 I.R.S. Employer
incorporation or organization                                 Identification No.


3 World Financial Center, 29th Floor
New York, NY    Attn.:  Andre Anderson                              10285
--------------------------------------                              -----
Address of principal executive offices                             Zip code

Registrant's telephone number, including area code:  (212) 526-3183

        Securities registered pursuant to Section 12(b) of the Act: None

           Securities registered pursuant to Section 12(g) of the Act:


           4,827,500 DEPOSITORY UNITS OF LIMITED PARTNERSHIP INTEREST
           ----------------------------------------------------------
                                 Title of Class

Indicate by check mark whether the Registrant (1) has filed all reports required
to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during
the preceding 12 months (or for shorter period that the Registrant was required
to file such reports), and (2) has been subject to such filing requirements for
the past 90 days.
                                Yes  X    No
                                    ---      ---

Indicate by check mark if disclosure of delinquent filers pursuant to Item
405 of Regulation S-K is not contained herein, and will not be contained, to
the best of the Registrant's knowledge, in definitive proxy or information
statements incorporated by reference in Part III of this Form 10-K or any
amendment to this Form 10-K.   X
                              ---

State the aggregate market value of the voting stock held by non-affiliates of
the registrant: Not applicable.

DOCUMENTS INCORPORATED BY REFERENCE:  Portions of Parts I, II, III and IV are
incorporated by reference to the Partnership's Annual Report to Unitholders for
the year ended December 31, 1999.

                                                                               1
<PAGE>


                                     PART I

Item 1.  Business

(a)  General Development of Business
     -------------------------------

Senior Income Fund L.P. (the "Partnership", formerly Shearson Lehman Senior
Income Fund Limited Partnership), a Delaware limited partnership, was formed on
October 14, 1986 pursuant to a Limited Partnership Agreement, as amended and
restated on March 17, 1987 pursuant to an Amended and Restated Limited
Partnership Agreement (the "Partnership Agreement"). The Partnership was formed
for the purpose of acquiring a general partnership interest in Shearson August
Property Partnership, a California general partnership (the "Property
Partnership"), with August Financial Partners II ("AFP-II") an affiliate of
August Financial Corporation ("August").

The general partner of the Partnership is Senior Income Fund Inc. (the
"General Partner", formerly Shearson Lehman Senior Income Fund, Inc.), a
Delaware corporation, and wholly owned subsidiary of Lehman Brothers Inc.
(formerly Shearson Lehman Brothers Inc.).

On November 21, 1996, the Partnership purchased the general partnership interest
of the successor to AFP-II for a purchase price of $850,000. As a result of such
purchase, all of the Property Partnership's assets were distributed to the
Partnership and the Property Partnership was dissolved. Accordingly, all sale
proceeds received upon a sale of any property belong to the Partnership and no
amount is owed to AFP-II. The Partnership will continue until December 31, 2036
unless terminated earlier pursuant to the provisions of the Partnership
Agreement.

The Property Partnership was formed to acquire, operate and ultimately sell four
specified residential properties for senior citizens (the "Properties") as
follows: (i) Pacific Inn, a 134-unit apartment complex located in Torrance,
California; (ii) Nohl Ranch Inn, a 133-unit apartment complex located in
Anaheim, California; (iii) Ocean House, a 121-unit apartment complex located in
Santa Monica, California, and; (iv) Prell Gardens, a 102-unit apartment complex
located in Van Nuys, California.

On August 1, 1997, the Partnership closed on the sale of three of its four
Properties -- Prell Gardens, Nohl Ranch and Pacific Inn, for net proceeds of
$30,148,357. On October 13, 1998, the Partnership closed on the sale of the
remaining property, Ocean House, for a gross sales price of $5,172,750 less a
credit for cost of repairs due to earthquake damage of $4,174,171, resulting in
a net selling price of $988,579. Although the Partnership's leasehold interest
in Ocean House was sold, the ground lessor has not released the Partnership from
its continuing contingent liability associated with the ground lease. The
Partnership is not expected to be terminated until this contingent liability is
removed. Reference is made to Item 7 for a discussion of the sales.

(b)  Financial Information about Industry Segments
     ---------------------------------------------

Substantially all of the Partnership's revenues, operating profit or loss and
assets relate solely to its interest as general partner of the Property
Partnership whose operating profit or loss and assets relate to its ownership
and operation of the Properties, until November 21, 1996, at which time the
Partnership purchased AFP-II's general partner interest in the Property
Partnership, as noted in Item 1(a).

(c)  Narrative Description of Business
     ---------------------------------

The Partnership's principal objectives at inception were:

     (1) to provide quarterly cash distributions a portion of which will be "tax
         sheltered;"
     (2) to preserve and protect capital;
     (3) to achieve long-term appreciation in the value of the Properties for
         distributions upon sale of the Properties.

Presently, the General Partner is in the process of winding up the Partnership's
affairs and expects to terminate the Partnership subsequent to its removal as
obligor of the Ocean House contingent liability.

                                                                               2
<PAGE>


(d)  Employees
     ---------

The Partnership has no employees.


Item 2.  Properties

As of December 31, 1999, all four of the Partnership's properties had been sold.


Item 3.  Legal Proceedings

The Registrant is not subject to any material pending legal proceedings.


Item 4.  Submission of Matters to a Vote of Security Holders

No matters were submitted to a vote of the holders of Units ("Limited Partners")
during the fourth quarter of the year for which this report is filed.


                                     PART II

Item 5.  Market for the Partnership's Limited Partnership
         Interests and Related Security Holder Matters

(a)  Market Price Information

There is no established trading market for the units nor is there anticipated to
be.

(b)  Holders

As of December 31, 1999, there were 3,303 Limited Partners of record.

(c)  Cash Distributions per Unit

<TABLE>
<CAPTION>
                                              1999              1998
            --------------------------------------------------------
            <S>                            <C>               <C>
            1st Quarter                    $ 0.000           $ 0.000
            2nd Quarter                      0.000             0.000
            3rd Quarter                      0.000             0.000
            Special Distribution             0.000             1.111(1)
            4th Quarter                      0.000             0.000
                                           -------------------------
            Total                          $ 0.000           $ 1.111
            --------------------------------------------------------
<FN>
     (1) On November 17, 1998, the Partnership paid a cash distribution in the
         amount of $1.11 per Unit representing proceeds from the sale of Ocean
         House and a portion of the Partnership's cash reserves.
</FN>
</TABLE>

As a result of the sale of Ocean House, the Partnership made a special
distribution of $1.11 per Unit on November 17, 1998, representing net sales
proceeds and a portion of the Partnership's cash reserves. The remaining
reserves will be used to pay the Partnership's liabilities and expenses through
termination. If any proceeds remain, the Partnership intends to make another
distribution upon termination.

                                                                               3
<PAGE>


Item 6.  Selected Financial Data

<TABLE>
<CAPTION>
(Dollars in thousands,
 except per Unit data)              1999         1998         1997         1996         1995
----------------------------------------------------------------------------------------------
<S>                            <C>          <C>          <C>          <C>          <C>
Rental Income                  $     --     $  3,155     $  8,233     $ 10,782     $ 10,838
Interest and Other Income            49          272          344          205          199
Total Income                         49        3,427        8,577       13,305(2)    11,037
Income (Loss) From Operations      (208)         277          931        3,154       (7,877)(3)
Gain On Sale Of Properties           --        2,072       11,840           --           --
Net Income (Loss)                  (208)       2,349       12,771(4)     3,154       (7,877)(3)
Income (Loss) From Operations
  Per Unit(1)                      (.04)         .06          .19          .65        (1.63)
Net Income (Loss) Per Unit(1)      (.04)         .49         2.58          .65        (1.63)
Cash Distributions Per Unit(1)     0.00         1.11         5.82          .90          .30
                               ------------------------------------------------------------
Total Assets                   $    839     $  1,111     $  5,547     $ 22,574     $ 22,976
----------------------------------------------------------------------------------------------
<FN>
     (1) Total Units outstanding: 4,827,500.

     (2) Includes net insurance settlement income of $2,318,387, in connection
         with the Partnership's settlement of its litigation with its insurance
         carrier in November 1996.

     (3) Includes the recognition of a $8,712,292 loss on the write-down of real
         estate assets in compliance with Financial Accounting Standards No. 121
         in 1995.

     (4) Includes the recognition of a $11,839,814 gain on sale of three
         properties.
</FN>
</TABLE>


Item 7.  Management's Discussion and Analysis of Financial
         Condition and Results of Operations

(a)  Liquidity and Capital Resources
     -------------------------------

On June 9, 1997, the Partnership executed an agreement with an unaffiliated
third party, MBK Senior Properties, Ltd. (the "Buyer"), to sell the
Partnership's four properties (the "Sale") for $36,300,000, subject to
adjustments and prorations for closing costs, and a credit for the cost to
repair earthquake damage at the Ocean House property. On August 1, 1997, the
Partnership closed the Sale for three of the four properties - Prell Gardens,
Nohl Ranch and Pacific Inn, for net proceeds of $30,148,357 and a gain on the
sale of $11,839,814. The Partnership's fourth property, Ocean House, was sold on
October 13, 1998 to MBK Senior Living Communities, Ltd., formerly known as MBK
Senior Properties, Ltd. The gross selling price was $5,172,750, less a credit
for cost of repairs due to earthquake damages of $4,174,171, resulting in a net
selling price of $998,579 and a gain on the sale of $2,072,451, including the
assignment of the land lease obligation. The Partnership remains contingently
liable under the terms of the Ocean House ground lease.

As a result of the Sale, the Partnership suspended the payment of quarterly cash
distributions beginning with the second quarter 1997 distribution which would
have been paid on or about August 15, 1997. On August 25, 1997, the Partnership
paid a cash distribution in the amount of $5.75 per Unit, representing proceeds
from the sale of the first three properties and cash flow from operations for
the second quarter of 1997. With the completion of the Ocean House sale, the
Partnership made a special distribution of $1.11 per Unit, on November 17, 1998,
representing the net sales proceeds and a portion of the Partnership's cash
reserves.

Although the Partnership's leasehold interest in Ocean House was sold, the
General Partner has not obtained a release from the ground lessor of the
Partnership's continuing contingent liability associated with the ground lease.
The General Partner has explored various means by which to release or protect
the Partnership from this contingent liability, and will continue to do so.
However, until this is accomplished, the General Partner expects that the
Partnership will not be terminated, and the remaining cash will continue to be
held in reserve. While the General Partner is attempting to wind up the affairs
of the Partnership and terminate it, there can be no assurance as to when the
General Partner will be successful in doing so.

At December 31, 1999, the Partnership had cash and cash equivalents of $839,125
compared to $1,060,585 at December 31, 1998. The decrease is primarily due to a
reduction in income due to the sale of Ocean House in 1998.

                                                                               4
<PAGE>


Accounts payable and accrued expenses were $46,440 at December 31, 1999 compared
to $92,716 at December 31, 1998. The change is primarily due to reduced expenses
due to the sale of Ocean House in 1998.

Market Risk
-----------
The Partnership's principal market risk exposure is interest rate risk. As a
result of the sale of Ocean House, the Partnership no longer has any properties
or debt, and its assets consist primarily of cash and cash equivalents.
Accordingly, the Partnership's interest risk exposure is primarily limited to
interest earned on the Partnership's cash and cash equivalents, which are
invested at short-term rates. Such risk is not considered material to the
Partnership's operations.

Y2K Initiatives
---------------

The Partnership has previously discussed the nature and progress of its plans to
become Year 2000 ready. In late 1999, the Partnership completed its remediation
and testing of systems. As a result of those planning and implementation
efforts, the Partnership experienced no significant disruptions in mission
critical information technology and non-information technology systems and
believes those systems successfully responded to the Year 2000 date change. The
Partnership is not aware of any material problems resulting from Year 2000
issues, either with its products, its internal systems, or the products and
services of third parties. The Partnership will continue to monitor its mission
critical computer applications and those of its suppliers and vendors throughout
the year 2000 to ensure that any latent Year 2000 matters that may arise are
addressed promptly.

(b)  Results of Operations
     ---------------------

1999 versus 1998
----------------

Partnership operations resulted in net loss of $208,442 for the year ended
December 31, 1999, compared to net income of $2,349,347 for the year ended
December 31, 1998. The decrease is primarily a result of reductions in income
due to the sale of Ocean House in 1998.

Rental income for the year ended December 31, 1999 was $-0-, compared to
$3,155,478 in 1998. The decrease is due to the sale of the last property.

Primarily as a result of the sale of Ocean House, all expense categories
decreased from the 1998 periods to the 1999 periods.

1998 versus 1997
----------------

Partnership operations resulted in net income of $2,349,347 for the year ended
December 31, 1998, compared to $12,770,868 for the year ended December 31, 1997.
Net income in 1997 included a $11,839,814 gain on sale of Prell Gardens, Nohl
Ranch and Pacific Inn, while net income in 1998 included a $2,072,451 gain on
the sale of Ocean House. Excluding these gains, net income from operations
totaled $276,896 in 1998 compared with $931,054 in 1997. The decrease is
primarily due to a decrease in rental income, as a result of the sale of three
of the Properties in 1997, which exceeded the decrease in all expense
categories. The decrease also reflects the sale of Ocean House in October 1998.

Primarily as a result of the sale of three of the Partnership's Properties on
August 1, 1997, rental income and all expense categories decreased from 1997 to
1998. Loss on real estate held for disposition was $-0- in 1998 compared to
$48,000 in 1997. The 1997 amount represents costs associated with balcony
restoration at Ocean House which were expensed through the loss provision in
compliance with Statement of Financial Accounting Standards No. 121.


Item 8.  Financial Statements and Supplementary Data

Incorporated by reference to the Partnership's Annual Report to Unitholders for
the year ended December 31, 1999, which is filed as an exhibit under Item 14.

                                                                               5
<PAGE>


Item 9.  Changes in and Disagreements with Accountants
         on Accounting and Financial Disclosure

None.


                                    PART III

Item 10. Directors and Executive Officers of the Partnership

The Partnership has no directors or officers. The General Partner has general
responsibility for all aspects of the Partnership's operation. Certain of the
officers and directors of the General Partner are also officers and employees of
Lehman Brothers Inc.

Certain officers and directors of the General Partner are now serving (or in the
past have served) as officers or directors of entities which act as general
partners of a number of limited partnerships which have sought protection under
the provisions of the Federal Bankruptcy Code. The partnerships which have filed
bankruptcy petitions own assets which have been adversely affected by the
economic conditions in the markets in which that asset is located and,
consequently, the partnerships sought protection of the bankruptcy laws to
protect the partnerships' assets from loss through foreclosure.

The directors and principal officers of the General Partner are listed below.

     Name                  Office
     ----                  ------
     Michael T. Marron     Director, President and Chief Financial Officer
     Rocco F. Andriola     Director, Vice President

Michael T. Marron, 36, is a Vice President of Lehman Brothers and has been a
member of the Diversified Asset Group since 1990 where he has actively
managed and restructured a diverse portfolio of syndicated limited
partnerships.  Prior to joining Lehman Brothers, Mr. Marron was associated
with Peat Marwick Mitchell & Co. serving in both its audit and tax divisions
from 1985 to 1989.  Mr. Marron received a B.S. degree from the State
University of New York at Albany and an M.B.A. degree from Columbia
University and is a Certified Public Accountant.

Rocco F. Andriola, 41, is a Managing Director of Lehman Brothers in its
Diversified Asset Group and has held such position since October 1996.  Mr.
Andriola also serves as the Director of Global Corporate Services for
Lehman.  Since joining Lehman in 1986, Mr. Andriola has been involved in a
wide range of restructuring and asset management activities involving real
estate and other direct investment transactions.  From June 1991 through
September 1996, Mr. Andriola held the position of Senior Vice President in
Lehman's Diversified Asset Group.  From June 1989 through May 1991, Mr.
Andriola held the position of First Vice President in Lehman's Capital
Preservation and Restructuring Group.  From 1986 to 1989, Mr. Andriola served
as a Vice President in the Corporate Transactions Group of Shearson Lehman
Brothers' office of the general counsel.  Prior to joining Lehman, Mr.
Andriola practiced corporate and securities law at Donovan Leisure Newton &
Irvine in New York.  Mr. Andriola received a B.A. from Fordham University, a
J.D. from New York University School of Law, and an LL.M in Corporate Law
from New York University's Graduate School of Law.


Item 11. Executive Compensation

The Directors and Officers of the General Partner do not receive any salaries or
other compensation from the Partnership. See Item 13, "Certain Relationships and
Related Transactions," for a description of certain transactions of the General
Partner and its affiliates with the Partnership.

                                                                               6
<PAGE>


Item 12. Security Ownership of Certain Beneficial Owners and Management

(a)  Security ownership of certain beneficial owners.

As of December 31, 1999, one party was known by the Partnership to be the
beneficial owner of more than five percent of the Units of the Partnership. The
owner, LAVRA, Inc., owns a total of 585,482.75 Units or 12.1% of the Units in
one account. LAVRA's address is 245 Fischer Avenue, Suite D-1, Costa Mesa,
California, 92626.

(b)  Security ownership of management.

Officers and Directors of the General Partner owned no units of the Partnership
as of December 31, 1999.

(c)  Changes in control.

None.


Item 13. Certain Relationships and Related Transactions

For fees paid and reimbursed to the General Partner or its affiliates during
1999, 1998 and 1997, see Note 5, "Transactions with Related Parties," to the
Financial Statements which is incorporated by reference to the Partnership's
Annual Report to Unitholders for the year ended December 31, 1999, which is
filed as an exhibit under Item 14.

                                                                               7
<PAGE>


                                     PART IV

Item 14. Exhibits, Financial Statement Schedules and Reports on Form 8-K

(a) (1)  Financial Statements:

         Balance Sheets - At December 31, 1999 and 1998.................     (2)

         Statements of Partners' Capital (Deficit) - For the years ended
         December 31, 1999, 1998 and 1997...............................     (2)

         Statements of Operations - For the years ended
         December 31, 1999, 1998 and 1997...............................     (3)

         Statements of Cash Flows - For the years ended
         December 31, 1999, 1998 and 1997...............................     (4)

         Notes to the Financial Statements..............................     (5)

         Report of Independent Accountants..............................     (9)

(a) (2)  Financial Statement Schedules:

         No schedules are presented because the information is not applicable or
         is included in the Financial Statements or the notes thereto.

    (1)  Incorporated  by  reference  to the  Partnership's  Annual  Report  to
         Unitholders for the year ended December 31, 1999,  filed as an exhibit
         under Item 14.

(a) (3)  Exhibits

3.1      The Partnership's Amended and Restated Agreement of Limited
         Partnership, Dated March 17, 1987, is hereby incorporated by reference
         to Exhibit A to the Prospectus contained in Registration Statement No.
         33-9921, which registration Statement (the "Registration Statement")
         was declared effective by the Securities and Exchange Commission on
         January 30, 1987.

3.2      The Capital Contribution Agreement by and among the General Partner
         and Shearson Group is hereby incorporated by reference to Exhibit 3.2
         to the Registration Statement.

10.1     Form of the Management Agreement dated as of April 5, 1988 between the
         Partnership and the Operator is incorporated by reference to Exhibit
         10.2 to the Registration Statement.

10.2     The form of Property Partnership Agreement between the Partnership and
         the Property Partner is hereby incorporated by reference to Exhibit
         10.6 to the Registration Statement.

10.3     The form of Purchase Agreement concerning the acquisition of the
         Properties is hereby incorporated by reference to Exhibit No. 10.4 to
         the Registration Statement.

13.1     Annual Report to Unitholders for the year ended December 31, 1999.

27       Financial Data Schedule.

(b)      Reports on Form 8-K:

         None.

                                                                               8
<PAGE>


                                   SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) of the Securities and
Exchange Act of 1934, the Partnership has duly caused this report to be signed
on its behalf by the undersigned, thereunto duly authorized.



                      SENIOR INCOME FUND L.P.

                      BY: SENIOR INCOME FUND INC.
                          General Partner



Date:  March 28, 2000     BY:    /s/Michael T. Marron
                                 --------------------
                          Name:  Michael T. Marron
                          Title: Director, President and Chief Financial Officer


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



                      SENIOR INCOME FUND L.P.

                      BY: SENIOR INCOME FUND INC.
                          General Partner



Date:  March 28, 2000     BY:    /s/Michael T. Marron
                                 --------------------
                          Name:  Michael T. Marron
                          Title: Director, President and Chief Financial Officer



Date:  March 28, 2000     BY:    /s/Rocco F. Andriola
                                 --------------------
                          Name:  Rocco F. Andriola
                          Title: Director, Vice President

                                                                               9