<PAGE>

===============================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                              Washington, DC 20549
                                   FORM 10-KSB

                  Annual Report Pursuant to Section 13 or 15(d)
                       of Securities Exchange Act of 1934

                                                               Commission File
For the fiscal year ended December 31, 1998                    Number  2-83272
                          -----------------                    ---------------

               WINTHROP INTERIM PARTNERS I, A LIMITED PARTNERSHIP
               --------------------------------------------------
        (Exact name of small business issuer as specified in its charter)

          Maryland                                         04-2787751
  -----------------------                           -------------------------
  (State of organization)                           (I.R.S. Employer I.D No.)

5 Cambridge Center, Cambridge, Massachusetts                          02142
--------------------------------------------                        ----------
  (Address of principal executive offices)                          (Zip Code)

       Registrant's telephone number including area code: (617) 234-3000
                                                          --------------
        Securities registered pursuant to Section 12(b) of the Act: None
                                                                    ----
          Securities registered pursuant to Section 12(g) of the Act:

                      Units of Limited Partnership Interest
                      -------------------------------------
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 such 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-B is not contained herein, and will not be contained, to the
best of registrant's knowledge, in definitive proxy or information statements
incorporated by reference in Part III of this Form 10-KSB or any amendment to
this Form 10-KSB. [ ]

Registrant's revenues for its most recent fiscal year were $0.00.

No market exists for limited partnership units of the Registrant, and,
therefore, no aggregate market value can be determined.

                       DOCUMENTS INCORPORATED BY REFERENCE

                                      None

===============================================================================

<PAGE>



                                     PART I

Item 1.  Business.
         ---------
         Winthrop Interim Partners I, A Limited Partnership (the "Registrant"),
was organized under the Revised Uniform Limited Partnership Act of the State of
Maryland on April 14, 1983, for the purpose of investing in general
partnerships, limited partnerships and joint ventures (the "Syndicating
Partnerships") which own real estate and other property.

         The General Partners of the Registrant are Two Winthrop Properties,
Inc., a Massachusetts corporation ("Two Winthrop" or the "Managing General
Partner"), and Linnaeus-Phoenix Associates Limited Partnership, a Massachusetts
limited partnership ("Linnaeus-Phoenix"). Two Winthrop is the managing general
partner of the Registrant.

         From June 23, 1983 to January 1984, the Registrant sold pursuant to a
Registration Statement filed with the Securities and Exchange Commission 100,000
units of limited partnership interest (the "Units") at a purchase price of $500
per Unit, representing gross capital contributions of $50,000,000.

         During 1983 and 1984, the Registrant invested in six Syndicating
Partnerships by making capital contributions of $2,904,000. Also during this
period, the Registrant pledged approximately $46,000,000 as collateral to secure
loans and letters of credit obtained by the Syndicating Partnerships totaling
approximately $130,000,000. As of September 24, 1984, all such loans, letters of
credit and guarantees had been repaid or released and the Registrant's
collateral had been returned. On September 24, 1984, the Registrant, in
accordance with its original business plan, distributed $50,000,000 to its
limited partners ("Limited Partners"), an amount equal to their original capital
contributions. In order to accomplish this distribution, and to distribute to
the General Partners their allocable share of Cash Available for Distribution
(as defined in the partnership agreement for the Registrant), the General
Partners contributed approximately $3,000,000 to the capital of the Registrant.

         As of March 1, 1999, the Registrant retained interests in two
Syndicating Partnerships. Two of the Syndicating Partnerships, RC Commercial and
RC Apartments, owned interests in a single mixed-use building referred to as
"River City" which was foreclosed on in January 1998. See "Dispositions" below.
The remaining two Syndicating Partnerships own interests in office buildings
referred to as "One Financial Place" and "Nineteen New York Properties",
respectively. However, it is expected that the remaining assets of One Financial
Place and Nineteen New York 



<PAGE>





Properties will be lost through foreclosure in 1999 and such Syndicating 
Partnerships dissolved.

         The only business of the Registrant was investing in Syndicating
Partnerships. The Registrant's business is currently limited to holding and
monitoring its investments in the Syndicating Partnerships. The Registrant will
not make any further investments.

Employees

         The Registrant does not have any employees. Services are performed for
the Registrant by the General Partners and agents retained by it.

Dispositions

         River City. The River City property was owned by two Syndicating
Partnerships in which the Registrant had invested. The Registrant retained a
1.4% and .5% interest in RC Commercial Limited Partnership and RC Apartments
Limited Partnership (collectively, the "RC Partnerships"), respectively.

         The River City property conducted operations under a provisional
workout arrangement with The Department of Housing and Urban Development ("HUD")
since 1987 when the property first became in default under its mortgage loan
obligations with HUD. In December 1996, HUD sold the mortgage loan at public
action. The successful bidder for the mortgage loan was an affiliate of the
Managing General Partner, who purchased the loan to forestall foreclosure
proceedings while efforts were made to restructure the debt. In 1997, the
mortgage loan was sold and, in January 1998 due to the value of the River City
property being less than the outstanding indebtedness, the River City property
was foreclosed upon by the noteholder. The amount of taxable income in 1998
attributable to the Partnership as a result of this foreclosure is expected to
be $1,130,000 or $11.00 per unit.


Item 2.  Description of Property.
         ------------------------
         Other than the investments in Syndicating Partnerships set forth below,
the Registrant does not own any property.


<PAGE>



         The table below describes the property in which the Registrant
currently, through the respective Syndicating Partnership, retains an ownership
interest.

<TABLE>
<CAPTION>
                                                               Registrant Capital
                                                               Contribution               Percentage
                                                               to Syndicating             Interest
Property                      Type of Property                 Partnerships               of Registrant(1)
--------                      ----------------                 ------------------         ----------------
<S>                           <C>                              <C>                        <C>
One Financial Place           Commercial Office                $  200,000                 1.0
                                Building

Nineteen New York             Commercial Office                 2,500,000                 5.2
  Properties                    Properties                     ----------

                                                               $2,700,000
                                                               ==========
</TABLE>
---------------
(1)   Represents the Registrant's interest in operating profits, losses and cash
      distributions of the Syndicating Partnerships. The Registrant's interest
      in profits, losses, and cash distributions in connection with a sale or
      refinancing of all or part of a property owned by a Syndicating
      Partnership may differ from the percentages set forth in the table above.

         One Financial Place. Registrant owns an interest in One Financial Place
Limited Partnership, a Syndicating Partnership which holds an indirect interest
in One Financial Place Partnership ("OFPP"). OFPP owns and operates a 39-story
office building in Chicago, Illinois. Due to declining market conditions
resulting in lease renewals at rates insufficient to satisfy its debt service,
OFPP filed a "pre-packaged" bankruptcy plan under Chapter 11 of the U.S.
Bankruptcy Code on November 28, 1994. The Plan was approved on January 31, 1995,
and provides for, among other matters, an extension of the first mortgage loan
until October 1998. The restructuring permitted OFPP to retain ownership of its
property through 1998. However, OFPP is in default on the loan and the lender
has scheduled a foreclosure sale for April 27, 1999. Therefore, the Registrant
presently carries the interest at a net realizable value of zero.

         19NY. The Registrant owns an interest in 1626 New York Associates
Limited Partnership ("1626"), a Syndicating Partnership which holds an interest
in Nineteen New York Properties ("19NY"). 19NY originally acquired 19 commercial
properties in 1984. As of March 1, 1999, 19NY owned one property. It is expected
that the remaining property will be foreclosed upon in 1999.

         In February 1996, 19NY restructured the mortgage loans on four
commercial properties (one of which was sold in January 1998), and conveyed one
other property to its mortgage lender in consideration for the release of a
mortgage loan held by that lender on another property. In addition, the loan
encumbering the other two properties was refinanced in 1997. The mortgage loans
on the four commercial properties (the "Zeus Loans") were 


<PAGE>





scheduled to mature in February 1998, however, the lender has extended these
loans on a month by month basis. In October 1998, 19NY conveyed to the lender's
designee its ownership interest in four of its remaining five properties and
restructured its loan with respect to its remaining property. Given the level of
debt encumbering the remaining property, it is likely 19NY will not realize any
proceeds from the disposition of the remaining property, whether by sale or
through mortgage foreclosure. Therefore, the Registrant presently carries the
interest at a net realizable value of zero.

         See Item 6 "Management's Discussion and Analysis or Plan of Operation"
for information relating to future operations of the Registrant and the
Syndicating Partnerships.


Item 3.  Legal Proceedings.
         ------------------
         There are no material pending legal proceedings to which the Registrant
is a party or of which any of its property is subject.


Item 4.  Submission of Matters to a Vote of Security Holders.
         ----------------------------------------------------
          No matter was submitted to a vote of security holders during the
period covered by this report.



<PAGE>



                                     PART II

Item 5.           Market for the Registrant's Common Equity and Related 
                  Stockholder Matters.
                  -----------------------------------------------------
         The Registrant is a partnership and thus has no common stock. There is
no established public trading market for the Units. Trading in the Units is
sporadic and occurs solely through private transactions.

         As of March 15, 1999, there were 1,736 holders of 99,805 outstanding
Units of record. Limited Partners holding a total of 195 Units have abandoned
their Units.

         For the year ended December 31, 1984, $50,000,000 was distributed to
the Limited Partners; an amount equal to their original capital contributions.
There were no cash distributions paid or accrued for the years ended December
31, 1985 through 1998. See "Item 6 Management's Discussion and Analysis or Plan
of Operation," for information relating to the Registrant's ability to make
future distributions.



<PAGE>


Item 6.    Management's Discussion and Analysis of Financial Condition and 
           Results of Operations.
           ---------------------------------------------------------------

           This Item should be read in conjunction with the Consolidated
           Financial Statements and other Items contained elsewhere in this
           Report.

           The matters discussed in this Form 10-K contain certain
           forward-looking statements and involve risks and uncertainties
           (including changing market conditions, competitive and regulatory
           matters, etc.) detailed in the disclosure contained in this Form 10-K
           and the other filings with the Securities and Exchange Commission
           made by the Registrant from time to time. The discussion of the
           Registrant's liquidity, capital resources and results of operations,
           including forward-looking statements pertaining to such matters, does
           not take into account the effects of any changes to the Registrant's
           operations. Accordingly, actual results could differ materially from
           those projected in the forward-looking statements as a result of a
           number of factors, including those identified herein.

           Liquidity and Capital Resources

           The Registrant's business is currently limited to holding and
           monitoring its investments in the Syndicating Partnerships. The
           Registrant will not make any further investments. It is anticipated
           the properties the Syndicating Partnership's had invested in will be
           disposed of during 1999, at which the Registrant will be liquidated.

           The Registrant requires cash to pay operating expenses associated
           with reporting to its Limited Partners, including professional,
           printing and mailing costs. The General Partners have been making
           loans to the Registrant sufficient to pay these expenses and are
           expected to do so in future years to the extent that the Registrant
           does not receive cash flow from the Syndicating Partnerships
           sufficient to meet such cash requirements. However, there is no
           requirement under the Registrant's partnership agreement for the
           General Partners to continue to fund operating deficits. To date, the
           General Partners have advanced $271,867 to the Registrant, of which
           $38,692 was advanced in 1998. These loans are non-interest bearing
           and are to be repaid out of cash distributions, if any, which the
           Registrant receives from the Syndicating Partnerships. The loans are
           to be repaid prior to the Registrant making any cash distributions to
           its Limited Partners.

           The results of operations for the year ended December 31, 1998 as
           compared to 1997, remained relatively constant. It is expected that
           the Registrant's results of operations in future years will be
           similar to those in 1998. Due to continued operating deficits and the
           general market conditions affecting the assets of the Syndicating
           Partnerships, the Registrant determined it was necessary to write
           down to zero its investment in RC Commercial and RC Apartments in
           1989, 1626 New York Associates Limited Partnership in 1990, and One
           Financial Place in 1991.

           It is not anticipated that the Registrant will receive cash
           distributions from any of the Syndicating Partnerships in the future.
           As of March 1, 1999, the two remaining Syndicating Partnerships, in
           which the Registrant is currently invested in, have incurred severe
           financial problems due to the deterioration of real estate markets
           across the United States.

           In September 1991, the Syndicating Partnership owning One Financial
           Place defaulted on its mortgage debt and unsecured loans. Since that
           date the Syndicating Partnership attempted to negotiate a
           restructuring agreement with its various lenders. In January, 1995, a
           restructuring became effective which, among other changes, cured the
           defaults on the Syndicating Partnership's various secured and
           unsecured loans, extended the maturity date of its mortgage loans by
           three years to October 1, 1998 and reduced its required debt service
           payments. Thus, the restructuring permitted the Syndicating
           Partnership to retain ownership of One Financial Place. At December
           31, 1998, the mortgage loans are in default. Given the level of debt
           encumbering the property, it is not likely that the Syndicating
           Partnership will realize any proceeds from the disposition of its
           property, whether by sale or mortgage foreclosure, which is expected
           to occur in 1999.

<PAGE>



Item 6.    Management's Discussion and Analysis of Financial Condition and 
           Results of Operations.(Continued)
           ---------------------------------------------------------------

           Liquidity and Capital Resources (Continued)

           For tax reporting purposes, the disposition of the property will
           cause taxable income to be allocated to the Registrant, but will not
           produce a cash distribution to the Registrant.

           The two Syndicating Partnerships owning River City have been in
           default on their mortgage debt since June 1987. The property was lost
           through foreclosure in January 1998. For financial reporting
           purposes, no gain or loss was recognized in 1998. For tax reporting
           purposes, the disposition of the property caused taxable income to be
           allocated to the Registrant, but did not produce a cash distribution
           to the Registrant.

           The Syndicating Partnership owning an interest in Nineteen New York
           Properties ("19NY") restructured its debt on four properties ("Zeus
           Properties"), which substantially reduced 19NY's current debt service
           requirements through February 1998. In February 1998, the lender on
           the Zeus Properties extended the maturity date on the debt to March
           31, 1998 and further extended the maturity date until September 30,
           1998.

           In October 1998, the 535 Fifth Avenue and 545 Fifth Avenue
           properties, which were owned by 19NY were conveyed to the lender in
           satisfaction of the mortgage debt encumbering these properties.
           Simultaneously, 19NY conveyed title (subject to the existing
           mortgages) in their 509 Fifth Avenue and 300 Park Avenue South
           properties to the lender. For financial statement purposes, no gain
           or loss will be recognized. For tax reporting purposes, the
           disposition of properties caused significant taxable income to be
           allocated to the Registrant in 1998 due to the recapture of tax
           benefits received in prior years. In addition, the debt securing
           19NY's remaining property, 757 Third Avenue, was restructured.

           On January 13, 1998, 19NY sold its 1372 Broadway property. All of the
           proceeds were used to partially satisfy its outstanding mortgage
           indebtedness, with the unsatisfied portion of the debt being
           reallocated among the remaining Zeus Properties.

           As of November 1, 1998, 19NY owns one commercial property in New York
           City. Given the level of debt encumbering the property, it is likely
           that 19NY will not realize any proceeds from the disposition of its
           remaining property, whether by sale or through mortgage foreclosure.
           The ultimate disposition of 19NY's property will cause taxable income
           to be allocated to the Registrant, but will not produce a cash
           distribution to the Registrant.

           Year 2000

           The Year 2000 Issue is the result of computer programs being written
           using two digits rather than four to define the applicable year. The
           Registrant is dependent upon the Managing General Partner and its
           affiliates for management and administrative services. Any computer
           programs or hardware that have date-sensitive software or embedded
           chips may recognize a date using "00" as the year 1900 rather than
           the year 2000. This could result in a system failure or
           miscalculations causing disruptions of operations, including, among
           other things, a temporary inability to process transactions, send
           invoices, or engage in similar normal business activities.

           During the first half of 1998, the Managing General Partner and its
           affiliates completed their assessment of the various computer
           software and hardware used in connection with the management of the
           Registrant. This review indicated that significantly all of the
           computer programs used by the Managing General Partner and its
           affiliates are off-the-shelf "packaged" computer programs which are
           easily upgraded to be Year 2000 compliant. In addition, to the extent
           that custom programs are utilized by the Managing General Partner and
           its affiliates, such custom programs are Year 2000 compliant.


<PAGE>



Item 6.    Management's Discussion and Analysis of Financial Condition and 
           Results of Operations. (Continued)
           ---------------------------------------------------------------

           Year 2000 (Continued)

           Following the completion of its assessment of the computer software
           and hardware, the Managing General Partner and its affiliates began
           upgrading those systems which required upgrading. To date,
           significantly all of these systems have been upgraded. The Registrant
           has to date not borne, nor is it expected that the Registrant will
           bear any significant cost, in connection with the upgrade of those
           systems to requiring remediation. It is expected that all systems
           will be remediated, tested and implemented during the first half of
           1999.

           To date, the Managing General Partner is not aware of any external
           agent with a Year 2000 issue that would materially impact the
           Registrant's results of operations, liquidity or capital resources.
           However, the Managing General Partner has no means of ensuring that
           external agents will be Year 2000 compliant. The Managing General
           Partner does not believe that the inability of external agents to
           complete their Year 2000 resolution process in a timely manner will
           have a material impact on the financial position or results of
           operations of the Registrant. However, the effect of non-compliance
           by external agents is not readily determinable.








<PAGE>




Item 7.    Financial Statements
           --------------------

                          WINTHROP INTERIM PARTNERS I,
                              A LIMITED PARTNERSHIP

                              Financial Statements

                          Year Ended December 31, 1998

                                Table of Contents


<TABLE>
<CAPTION>

                                                                                                            Page
                                                                                                            ----
<S>                                                                                                        <C>

Independent Auditors' Report...............................................................................F - 2

Financial Statements:

      Balance Sheets at December 31, 1998 and 1997.........................................................F - 3

      Statements of Operations for the Years Ended December 31, 1998 and 1997..............................F - 4

      Statements of Partners' Deficit for the Years Ended
              December 31, 1998 and 1997...................................................................F - 5

      Statements of Cash Flows for the Years Ended December 31, 1998 and 1997..............................F - 6

      Notes to Financial Statements........................................................................F - 7
</TABLE>













                                      F - 1


<PAGE>








                          Independent Auditors' Report


To the Partners of
Winthrop Interim Partners I,
A Limited Partnership:


We have audited the accompanying balance sheets of Winthrop Interim Partners I,
A Limited Partnership (a Maryland limited partnership) (the "Partnership") as of
December 31, 1998 and 1997, and the related statements of operations, changes in
partners' deficit and cash flows for the years then ended. These financial
statements are the responsibility of the Partnership's management. Our
responsibility is to express an opinion on these financial statements based on
our audits.

We conducted our audits in accordance with generally accepted auditing
standards. Those standards require that we plan and perform the audits to obtain
reasonable assurance about whether the financial statements are free of material
misstatement. An audit includes examining, on a test basis, evidence supporting
the amounts and disclosures in the financial statements. An audit also includes
assessing the accounting principles used and significant estimates made by
management, as well as evaluating the overall financial statement presentation.
We believe that our audits provide a reasonable basis for our opinion.

In our opinion, the financial statements referred to above present fairly, in
all material respects, the financial position of Winthrop Interim Partners I, A
Limited Partnership, as of December 31, 1998 and 1997, and the results of its
operations and its cash flows for the years then ended in conformity with
generally accepted accounting principles.




                                        Certified Public Accountants



New York, New York
March 26, 1999


                                      F - 2


<PAGE>


                          WINTHROP INTERIM PARTNERS I,
                          ----------------------------
                              A LIMITED PARTNERSHIP
                              ---------------------

                                 BALANCE SHEETS
                                 --------------

                                                             DECEMBER 31,
                                                    ---------------------------

ASSETS                                                 1998            1997
------                                              -----------     -----------

Cash                                                $        13     $        13
                                                    -----------     -----------

         Total Assets                               $        13     $        13
                                                    ===========     ===========

LIABILITIES AND PARTNERS' DEFICIT
---------------------------------

Liabilities:

Loans payable to affiliates                         $   271,867     $   233,175
                                                    -----------     -----------

         Total liabilities                              271,867         233,175
                                                    -----------     -----------

Partners' Deficit:

     Limited partners deficit -
         $500 stated value per unit - authorized,
             issued and outstanding - 99,990
                units as of December 31, 1998
                and 1997                             (2,787,589)     (2,749,284)
     General partners' capital                        2,515,735       2,516,122
                                                    -----------     -----------

         Total partners' deficit                       (271,854)       (233,162)
                                                    -----------     -----------

         Total liabilities and partners'  deficit   $        13     $        13
                                                    ===========     ===========





                       See notes to financial statements.

                                      F - 3

<PAGE>



                          WINTHROP INTERIM PARTNERS I,
                              A LIMITED PARTNERSHIP

                            STATEMENTS OF OPERATIONS

<TABLE>
<CAPTION>
                                                           YEARS ENDED DECEMBER 31,
                                                       --------------------------------
                                                            1998              1997
                                                       --------------    --------------
<S>                                                    <C>               <C>
Expenses:

    General and administrative                          $     38,692      $     34,830
                                                       --------------    --------------

         Total expenses                                       38,692            34,830
                                                       --------------    --------------

         Net loss                                       $    (38,692)     $    (34,830)
                                                       ==============    ==============


Net Loss Allocated:

    General Partners                                    $       (387)     $       (348)
                                                       ==============    ==============


    Limited Partners                                    $    (38,305)     $    (34,482)
                                                       ==============    ==============


Net loss per unit of limited partnership interest       $       (0.38)   $       (0.34)
                                                       ==============    ==============

</TABLE>





                       See notes to financial statements.

                                      F - 4

<PAGE>

                          WINTHROP INTERIM PARTNERS I,
                              A LIMITED PARTNERSHIP

                     STATEMENTS OF PARTNERS' DEFICIT FOR THE

                     YEARS ENDED DECEMBER 31, 1998 AND 1997

<TABLE>
<CAPTION>
                               Units of
                               Limited            Limited            General          Total
                             Partnership          Partners'          Partners'       Partners'
                               Interest           deficit            capital          deficit
                               --------           --------           ---------       --------

<S>                             <C>             <C>                <C>              <C>         
Balance - December 31, 1996     99,990          $ (2,714,802)      $  2,516,470     $  (198,332)

Net loss                             -               (34,482)              (348)        (34,830)
                                ------          ------------       ------------     -----------

Balance - December 31, 1997     99,990            (2,749,284)         2,516,122        (233,162)

Net loss                             -               (38,305)              (387)        (38,692)
                                ------          ------------       ------------     -----------

Balance - December 31, 1998     99,990          $ (2,787,589)      $  2,515,735     $  (271,854)
                                ======          ============       ============     ===========
</TABLE>












                       See notes to financial statements.

                                      F - 5




<PAGE>


                          WINTHROP INTERIM PARTNERS I,
                              A LIMITED PARTNERSHIP

                            STATEMENTS OF CASH FLOWS

<TABLE>
<CAPTION>
                                                      YEARS ENDED DECEMBER 31,
                                                  -------------------------------
                                                       1998              1997
                                                  --------------   --------------

<S>                                               <C>              <C>
CASH FLOWS FROM OPERATING ACTIVITIES:

Net loss                                          $     (38,692)   $     (34,830)
                                                  --------------   --------------

        Cash used in operating activities               (38,692)         (34,830)
                                                  --------------   --------------

CASH FLOWS FROM FINANCING ACTIVITIES:

Increase in loans payable to affiliate                   38,692           34,830
                                                  --------------   --------------

        Cash provided by financing activities            38,692           34,830
                                                  --------------   --------------

Decrease in cash                                             -                -

Cash at Beginning of Year                                    13               13
                                                  --------------   --------------

Cash at End of Year                               $          13    $          13
                                                  ==============   ==============

</TABLE>



                       See notes to financial statements.

                                      F - 6

<PAGE>



                          WINTHROP INTERIM PARTNERS I,
                              A LIMITED PARTNERSHIP

                          NOTES TO FINANCIAL STATEMENTS
                     YEARS ENDED DECEMBER 31, 1998 AND 1997


NOTE 1 - ORGANIZATION
------   ------------

              Winthrop Interim Partners I, A Limited Partnership (the
              "Partnership") was organized on April 14, 1983 under the Revised
              Uniform Limited Partnership Act of the State of Maryland. The
              Partnership will terminate on December 31, 2033, or sooner, in
              accordance with the terms of the Partnership's agreement.

NOTE 2 - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
------   ------------------------------------------

              Basis of Accounting

              The accompanying financial statements have been prepared on the
              accrual basis of accounting.

              Income Taxes

              Taxable income or loss of the Partnership is reported in the
              income tax returns of its partners. Accordingly, no provision for
              income taxes is made in the financial statements of the
              Partnership.

              Investments in Syndicating Partnerships

              The Partnership invested, as a general or limited partner, and
              initially maintained substantial equity interests in six general
              or limited partnerships and joint ventures (the "Syndicating
              Partnerships"), which own real estate or other property. As of
              December 31, 1998, the Partnership had interests in two
              Syndicating Partnerships (see Note 4).

              The Partnership accounts for these investments under the cost
              method of accounting. This accounting policy is being followed
              since the Partnership's period of substantial ownership was
              expected to be temporary and the Partnership does not control or
              significantly influence the day-to-day operations of the
              Syndicating Partnerships.

              In general, under the cost method of accounting for investments,
              the investment is recorded at cost, unless a permanent impairment
              in value to less than cost has occurred, in which case the
              carrying value of the investment is reduced. Any distributions are
              recorded as income, to the extent that they are a distribution of
              earnings.

NOTE 3 - TRANSACTIONS WITH RELATED PARTIES
------   ---------------------------------

              Two Winthrop Properties, Inc. ("Two Winthrop"), the managing
              general partner, is a wholly owned subsidiary of First Winthrop
              Corporation, which in turn is controlled by Winthrop Financial
              Associates, A Limited Partnership.

                                      F - 7


<PAGE>



                          WINTHROP INTERIM PARTNERS I,
                              A LIMITED PARTNERSHIP

                          NOTES TO FINANCIAL STATEMENTS
                     YEARS ENDED DECEMBER 31, 1998 AND 1997
                                   (Continued)


NOTE 3 - TRANSACTIONS WITH RELATED PARTIES (Continued)
------   ---------------------------------------------

              The general partners are entitled to 1% of any profits or losses
              for tax purposes and 1% of cash available for distribution. The
              general partners currently satisfy all the Partnership's cash
              requirements for general and administrative expenses through
              non-interest bearing loans to be repaid out of future cash flows
              from the Syndicating Partnerships. It is not practicable to
              estimate the fair value of these loans because it cannot be
              determined whether financing with similar terms and conditions
              would be available to the Partnership.

              Affiliates of the general partners earned various fees in
              connection with the formation and operations of the Syndicating
              Partnerships. During the liquidation stage of the Partnership, the
              general partners and their affiliates are entitled to receive
              certain distributions, as described in the Partnership agreement.

NOTE 4 - INVESTMENTS IN SYNDICATING PARTNERSHIPS
------   ---------------------------------------

              The Partnership invested a total of $2,904,000 and acquired
              initial general or limited partner equity interests ranging from
              75% to 99% in six Syndicating Partnerships. The Syndicating
              Partnerships entered into credit agreements with lending
              institutions to finance their organization and acquisition of
              properties prior to the admission of additional partners (the
              "Additional Partners"). The Partnership guaranteed the credit
              obligations of the Syndicating Partnership and pledged certain
              assets to the lending institutions. Upon admission of the
              Additional Partners, the obligations under the credit agreements
              were repaid and the Partnership's collateral was released.
              Subsequent to the admission of the Additional Partners, the
              Partnership's equity interest in each Syndicating Partnership was
              reduced to less than 6%.

              The Partnership currently accounts for all investments under the
              cost method of accounting. Due to continued operating deficits,
              debt defaults and the general market conditions affecting the
              assets, the Partnership determined in prior years that it was
              necessary to write down the investment in the two remaining
              Syndicating Partnerships to their net realizable value of zero.

              In January 1998, the River City property, which was owned by two
              of the Syndicating Partnerships in which the Partnership had
              invested in, was lost through foreclosure. For financial reporting
              purposes, no gain or loss was recognized.

              In October 1998, the 535 Fifth Avenue and 545 Fifth Avenue
              properties, which were owned by one of the Syndicating Partnership
              owning an interest in Nineteen New York properties ("19NY") were
              conveyed to the lender in satisfaction of the mortgage debt
              encumbering these properties. Simultaneously, 19NY also conveyed
              title (subject to the existing mortgages) in their 509 Fifth
              Avenue and 300 Park Avenue South properties to the lender. For
              financial statement purposes, no gain or loss will be recognized.
              In addition, the debt securing 19NY's remaining property, 757
              Third Avenue, was restructured.

                                      F - 8


<PAGE>



                          WINTHROP INTERIM PARTNERS I,
                              A LIMITED PARTNERSHIP

                          NOTES TO FINANCIAL STATEMENTS
                     YEARS ENDED DECEMBER 31, 1998 AND 1997
                                   (Continued)


NOTE 5 -  RECONCILIATION TO INCOME TAX METHOD OF ACCOUNTING
------    -------------------------------------------------

              The difference between the accrual method of accounting for income
              tax reporting and the accrual method of accounting used in the
              financial statements is related to the differences in recognition
              of the Partnership's share of the Syndicating Partnerships'
              results of operations. As of December 31, 1998 and 1997, the
              differences are as follows:


<TABLE>
<CAPTION>
                                                                                       1998                       1997 
                                                                                   -----------               -----------
<S>                                                                                <C>                      <C>

                      Net loss - financial statements                              $   (38,692)            $    (34,830)

                      Equity in Syndicating Partnerships
                         tax income (loss)                                          10,721,487                 (426,530)
                                                                                   -----------             ------------

                      Net income (loss) - income tax method                        $10,682,795             $   (461,360)
                                                                                   ===========              ===========
</TABLE>

























                                      F - 9



<PAGE>



Item 8. Changes in and Disagreements With Accountants on Accounting and
        Financial Disclosure.
        ---------------------------------------------------------------

         There were no disagreements with Imowitz Koenig & Co., LLP regarding
the 1998 or 1997 audits of the Partnership's financial statements.


<PAGE>




                                    PART III

Item 9. Directors, Executive Officers, Promoters and Control Persons; Compliance
        with Section 16(a) of the Exchange Act.
        ------------------------------------------------------------------------
         The Registrant has no officers or directors. The Managing General
Partner manages and controls substantially all of the Registrant's affairs and
has general responsibility and ultimate authority in all matters affecting its
business. As of March 1, 1999, the names of the directors and executive officers
of the Managing General Partner and the position held by each of them, are as
follows:

                                                      Has Served as
                            Position Held with the     a Director or
Name                       Managing General Partner   Officer Since
----                       ------------------------   -------------
Michael L. Ashner          Chief Executive Officer         1-96
                           and Director

Thomas C. Staples          Chief Financial Officer         1-99

Peter Braverman            Executive Vice President        1-96
                           and Director

Patrick J. Foye            Vice President - Residential    10-98
                           and Director

Carolyn Tiffany            Chief Operating Officer         10-95
                           and Clerk

         Michael L. Ashner, age 46, has been the Chief Executive Officer of
Winthrop Financial Associates, A Limited Partnership ("WFA") and the Managing
General Partner since January 15, 1996. From June 1994 until January 1996, Mr.
Ashner was a Director, President and Co-chairman of National Property Investors,
Inc., a real estate investment company ("NPI"). Mr. Ashner was also a Director
and executive officer of NPI Property Management Corporation ("NPI Management")
from April 1984 until January 1996. In addition, since 1981 Mr. Ashner has been
President of Exeter Capital Corporation, a firm which has organized and
administered real estate limited partnerships.

         Thomas C. Staples, age 43, has been the Chief Financial Officer of WFA
since January 1, 1999. From March 1996 through December 1998, Mr. Staples was
Vice President/Corporate Controller of WFA. From May 1994 through February 1996,
Mr. Staples was the Controller of the Residential Division of Winthrop
Management.


<PAGE>



         Peter Braverman, age 47, has been a Vice President of WFA and the
Managing General Partner since January 1996. From June 1995 until January 1996,
Mr. Braverman was a Vice President of NPI and NPI Management. From June 1991
until March 1994, Mr. Braverman was President of the Braverman Group, a firm
specializing in management consulting for the real estate and construction
industries. From 1988 to 1991, Mr. Braverman was a Vice President and Assistant
Secretary of Fischbach Corporation, a publicly traded, international real estate
and construction firm.

         Patrick J. Foye, age 41, has been Vice President-Residential and
Director of the Managing General Partner since October 1, 1998. Mr. Foye has
served as Executive Vice President of Apartment Investment and Management
Company ("AIMCO") since May 1998. Prior to joining AIMCO, Mr. Foye was a partner
in the law firm of Skadden, Arps, Slate, Meagher & Flom LLP from 1989 to 1998
and was Managing Partner of the firm's Brussels, Budapest and Moscow offices
from 1992 through 1994. Mr. Foye is also Deputy Chairman of the Long Island
Power Authority and serves as a member of the New York State Privatization
Council. He received a B.A. from Fordham College and a J.D. from Fordham
University Law School.

         Carolyn Tiffany, age 32, has been employed with WFA since January 1993.
From 1993 to September 1995, Ms. Tiffany was a Senior Analyst and Associate in
WFA's accounting and asset management departments. Ms. Tiffany was a Vice
President in the asset management and investor relations departments of WFA from
October 1995 to December 1997, at which time she became the Chief Operating
Officer of WFA.

         One or more of the above persons are also directors or officers of a
general partner (or general partner of a general partner) of the following
limited partnerships which either have a class of securities registered pursuant
to Section 12(g) of the Securities and Exchange Act of 1934, or are subject to
the reporting requirements of Section 15(d) of such Act: Winthrop Partners 79
Limited Partnership; Winthrop Partners 80 Limited Partnership; Winthrop Partners
81 Limited Partnership; Winthrop Residential Associates I, A Limited
Partnership; Winthrop Residential Associates II, A Limited Partnership; Winthrop
Residential Associates III, A Limited Partnership; 1626 New York Associates
Limited Partnership; 1999 Broadway Associates Limited Partnership; Nantucket
Island Associates Limited Partnership; One Financial Place Limited Partnership;
Presidential Associates I Limited Partnership; Riverside Park Associates Limited
Partnership; Springhill Lake Investors Limited Partnership; Twelve AMH
Associates Limited Partnership; Winthrop California 


<PAGE>



Investors Limited Partnership; Winthrop Growth Investors I Limited Partnership;
Southeastern Income Properties Limited Partnership; and Southeastern Income
Properties II Limited Partnership.

         Except as indicated above, neither the Registrant nor the Managing
General Partner has any significant employees within the meaning of Item 401(b)
of Regulation S-B. There are no family relationships among the officers and
directors of the Managing General Partner.

         Based solely upon a review of Forms 3 and 4 and amendments thereto
furnished to the Registrant under Rule 16a-3(e) during the Registrant's most
recent fiscal year and Forms 5 and amendments thereto furnished to the
Registrant with respect to its most recent fiscal year, the Registrant is not
aware of any director, officer or beneficial owner of more than ten percent of
the units of limited partnership interest in the Registrant that failed to file
on a timely basis, as disclosed in the above Forms, reports required by section
16(a) of the Exchange Act during the most recent fiscal year or prior fiscal
years.


Item 10.  Executive Compensation.
          -----------------------
         The Registrant is not required to and did not pay any compensation to
the officers or directors of the Managing General Partner. The Managing General
Partner does not presently pay any compensation to any of its officers and
directors (See "Item 12, Certain Relationships and Related Transactions").


Item 11. Security Ownership of Certain Beneficial Owners and Management.
         ---------------------------------------------------------------

         (a)      Security Ownership of Certain Beneficial Owners.

                  The General Partners own all the outstanding general
partnership interests. No person or group is known by the Registrant to be the
beneficial owner of more than 5% of the outstanding Units at March 15, 1999.

         (b)      Security Ownership of Management.

                  No executive officer, director or general partner of Two
Winthrop, Linnaeus-Phoenix or WFA own any Units of the Registrant, or has the
right to acquire beneficial ownership of additional Units.


<PAGE>




         (c)      Changes in Control.

                  There exists no arrangement known to the Registrant the
operation of which may at a subsequent date result in a change in control of the
Registrant.


Item 12. Certain Relationships and Related Transactions.
         -----------------------------------------------

         As of March 15, 1999, the Registrant has borrowed $_______ from the
General Partners to fund its operating expenses. No interest accrues on this
loan and no imputed interest is calculated for tax or other reporting purposes.
Since the Registrant is a limited partnership, it has no directors or officers.
In addition, the Registrant has had no transactions with individual officers or
directors of the Managing General Partner other than any indirect interest such
officers and directors may have in the compensation paid to the Managing General
Partner, or its affiliates by virtue of (i) their indirect ownership in WFA, the
indirect parent of the Managing General Partner, or (ii) their partnership
interests in Linnaeus-Phoenix

         The Registrant did not pay or accrue for the account of the General
Partners and their affiliates any compensation for the years ended December 31,
1997 and 1998.


Item 13. Exhibits and Reports on Form 8-K.
         ---------------------------------

         (a)      Exhibits - The exhibits listed in the accompanying Index to
Exhibits are filed as part of this Annual Report and incorporated in this Annual
Report as set forth in said index.

         (b)      Reports on Form 8-K:

                  No reports on Form 8-K were filed during the last quarter
covered by this report.



<PAGE>



                                   SIGNATURES


         Pursuant to the requirements of Section 13 or 15(d) 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.

                              WINTHROP INTERIM PARTNERS I,
                              A LIMITED PARTNERSHIP

                              By:  TWO WINTHROP PROPERTIES, INC.,
                                   Managing General Partner

                                   By:  /s/ Michael L. Ashner
                                        ---------------------------
                                        Michael L. Ashner
                                        Chief Executive Officer

                                   Date:  March 30, 1999

         Pursuant to the requirements of the Securities Exchange Act of 1934,
this report has been signed below by the following persons on behalf of the
Registrant and in the capacities and on the dates indicated.


Signature/Name                     Title             Date
--------------                     -----             ----

/s/ Michael Ashner          Chief Executive          March 30, 1999
------------------          Officer and Director
Michael Ashner


/s/ Thomas Staples          Chief Financial          March 30, 1999
----------------------      Officer
Thomas Staples



/s/ Peter Braverman         Executive Vice           March 30, 1999
----------------------      President and Director
Peter Braverman



<PAGE>




                                INDEX TO EXHIBITS


Exhibit Number                 Title of Document
--------------                 -----------------
 3.4.                          Agreement and Certificate of Limited
                               Partnership of Winthrop Interim Partners I, A
                               Limited Partnership, dated as of April 14, 1983
                               (incorporated herein by reference to the
                               Registrant's Registration Statement on Form S-11,
                               File No. 2-83272).

27                             Financial Data Schedule