<PAGE>   1

                                      1998
================================================================================
                UNITED STATES SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549

                                   FORM 10-QSB


(Mark One)
[X]      Quarterly Report Pursuant to Section 13 or 15(d) of the Securities
         Exchange Act of 1934 For the quarterly period ended September 30, 1998.
                                       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: 0-12742


                                SPIRE CORPORATION
--------------------------------------------------------------------------------
        (Exact Name of Small Business Issuer as Specified in Its Charter)


<TABLE>
<S>                                                                            <C>       
Massachusetts                                                                                            04-2457335
-------------------------------------------------------------------------------------------------------------------
(State or Other Jurisdiction of Incorporation or Organization                  (I.R.S. Employer Identification No.)
</TABLE>


One Patriots Park, Bedford, Massachusetts                             01730-2396
--------------------------------------------------------------------------------
(Address of Principal Executive Offices)                              (Zip Code)


                                  781-275-6000
--------------------------------------------------------------------------------
                (Issuer's Telephone Number, Including Area Code)


     Check whether the issuer: (1) filed all reports required to be filed by
Section 13 or 15(d) of the Exchange Act during the past 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 [ ]


     State the number of shares outstanding of each of the issuer's classes of
common equity, as of the latest practicable date. There were 3,243,766
outstanding shares of the issuer's only class of common equity, Common Stock,
$.01 par value, on October 30, 1998.


     Transitional Small Business Disclosure Format (Check One): Yes [ ]   No [X]


<PAGE>   2


                                SPIRE CORPORATION
                                      INDEX


<TABLE>
<CAPTION>
                                                                                Page Number
                                                                                -----------
<S>                                                                                <C>
PART I - FINANCIAL INFORMATION
------------------------------

    Condensed Consolidated Balance Sheets at                                          3
    September 30, 1998 (unaudited) and December 31, 1997

    Condensed Consolidated Statements of Operations                                   4
    For the Three Months Ended September 30, 1998 and 1997 and
    For the Nine Months Ended September 30, 1998 and 1997 (unaudited)

    Condensed Consolidated Statements of Cash Flows                                   5
    For the Nine Months Ended September 30, 1998 and 1997 (unaudited)

    Notes to Condensed Consolidated Financial Statements                              6

    Management's Discussion and Analysis of Financial                              7 - 11
    Condition and Results of Operations


PART II - OTHER INFORMATION
---------------------------

    Item 1.  Legal Proceedings                                                       11

    Item 6.  Exhibits and Reports on Form 8-K                                        11
</TABLE>







                                       2
<PAGE>   3


                        SPIRE CORPORATION AND SUBSIDIARY
                      CONDENSED CONSOLIDATED BALANCE SHEETS


<TABLE>
<CAPTION>
                                                                                     SEPTEMBER 30,      DECEMBER 31,
                                                                                         1998               1997
                                                                                     -------------      ------------
<S>                                                                                   <C>                <C>        
                                     ASSETS
CURRENT ASSETS
    Cash and cash equivalents                                                         $   481,844        $ 1,695,727
    Accounts receivable, trade:
        Amounts billed                                                                  2,853,017          3,012,701
        Retainage                                                                          54,133             69,772
        Unbilled costs                                                                    631,826            621,760
                                                                                      -----------        -----------
                                                                                        3,538,976          3,704,233
        Less allowance for doubtful accounts                                              107,900             40,000
                                                                                      -----------        -----------
            Net accounts receivable                                                     3,431,076          3,664,233
                                                                                      -----------        -----------

    Inventories (Note 2)                                                                1,848,132            988,580
    Deferred income taxes                                                                 349,578            300,000
    Prepaid expenses and other current assets                                             552,647            501,650
                                                                                      -----------        -----------
            Total current assets                                                        6,663,277          7,150,190
                                                                                      -----------        -----------

Property and equipment                                                                 24,729,255         24,015,445
    Less accumulated depreciation and amortization                                     19,927,103         19,242,437
                                                                                      -----------        -----------
            Net property and equipment                                                  4,802,152          4,773,008
                                                                                      -----------        -----------

Computer software costs (less accumulated amortization, $821,117 in 1998 and
    $810,466 in 1997)                                                                      40,484             51,135
Patents (less accumulated amortization, $576,726 in 1998 and $542,344 in 1997)            253,093            274,810
Other assets                                                                               16,146             19,679
                                                                                      -----------        -----------
                                                                                          309,723            345,624
                                                                                      -----------        -----------
                                                                                      $11,775,152        $12,268,822
                                                                                      ===========        ===========

                      LIABILITIES AND STOCKHOLDERS' EQUITY

CURRENT LIABILITIES
    Accounts payable                                                                  $ 1,592,534        $   903,581
    Accrued liabilities                                                                 1,308,943            859,093
    Advances on contracts in progress                                                     735,946            410,370
                                                                                      -----------        -----------
        Total current liabilities                                                       3,637,423          2,173,044
                                                                                      -----------        -----------

STOCKHOLDERS' EQUITY
    Common stock, $.01 par value; shares authorized 20,000,000;
        issued 3,795,926 shares in 1998 and 3,757,082 shares in 1997                       37,959             37,571
    Additional paid-in capital                                                          9,780,494          9,645,468
    Retained earnings (accumulated deficit)                                              (461,036)         1,632,427
                                                                                      -----------        -----------
                                                                                        9,357,417         11,315,466
    Treasury stock at cost, 552,160 shares                                             (1,219,688)        (1,219,688)
                                                                                      -----------        -----------
        Total stockholders' equity                                                      8,137,729         10,095,778
                                                                                      -----------        -----------
                                                                                      $11,775,152        $12,268,822
                                                                                      ===========        ===========
</TABLE>

     See accompanying notes to condensed consolidated financial statements.

                                       3
<PAGE>   4


                        SPIRE CORPORATION AND SUBSIDIARY
                 CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS


<TABLE>
<CAPTION>
                                                                THREE MONTHS ENDED              NINE MONTHS ENDED
                                                                   SEPTEMBER 30,                  SEPTEMBER 30,
                                                            --------------------------     ----------------------------
                                                               1998            1997            1998             1997
                                                            ----------      ----------     -----------      -----------
<S>                                                         <C>             <C>            <C>              <C>        
NET SALES AND REVENUES
    Contract research, service and license revenues         $2,869,262      $3,833,257     $ 8,604,736      $10,773,933
    Sales of manufacturing equipment                           850,655       2,342,777       3,002,998        6,285,648
                                                            ----------      ----------     -----------      -----------
        Total sales and revenues                             3,719,917       6,176,034      11,607,734       17,059,581
                                                            ----------      ----------     -----------      -----------

COSTS AND EXPENSES
    Cost of contract research, services and licenses         1,698,051       2,377,376       6,058,255        6,899,334
    Cost of manufacturing equipment                            963,082       1,597,626       2,705,442        4,213,078
    Selling, general and administrative expenses             1,396,092       1,486,400       4,949,017        4,284,212
                                                            ----------      ----------     -----------      -----------
        Total costs and expenses                             4,057,225       5,461,402      13,712,714       15,396,624
                                                            ----------      ----------     -----------      -----------

EARNINGS (LOSS) FROM OPERATIONS                               (337,308)        714,632      (2,104,980)       1,662,957

Interest income, net                                             2,030          10,294          20,517           13,940
                                                            ----------      ----------     -----------      -----------

Earnings (loss) before income taxes                           (335,278)        724,926      (2,084,463)       1,676,897

Income tax expense                                                  --              --           9,000          100,000
                                                            ----------      ----------     -----------      -----------

NET EARNINGS (LOSS)                                         $ (335,278)     $  724,926     $(2,093,463)     $ 1,576,897
                                                            ==========      ==========     ===========      ===========

EARNINGS (LOSS) PER SHARE OF COMMON STOCK - BASIC           $    (0.10)     $     0.23     $     (0.65)     $      0.52
                                                            ==========      ==========     ===========      ===========

EARNINGS (LOSS) PER SHARE OF COMMON STOCK - DILUTED         $    (0.10)     $     0.22     $     (0.65)     $      0.48
                                                            ==========      ==========     ===========      ===========

Weighted average number of common shares
    outstanding - basic                                      3,243,766       3,094,744       3,232,722        3,052,263
                                                            ==========      ==========     ===========      ===========

Weighted average number of common and  common
    equivalent shares  outstanding - diluted                 3,243,766       3,317,628       3,232,722        3,275,147
                                                            ==========      ==========     ===========      ===========
</TABLE>


     See accompanying notes to condensed consolidated financial statements.

                                       4

<PAGE>   5


                        SPIRE CORPORATION AND SUBSIDIARY
                 CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS


<TABLE>
<CAPTION>
                                                                                 NINE MONTHS ENDED SEPTEMBER 30,
                                                                                --------------------------------
                                                                                    1998                 1997
                                                                                -----------          -----------

<S>                                                                             <C>                  <C>        
Cash flows from operating activities:
    Net earnings (loss)                                                         $(2,093,463)         $ 1,576,897
    Adjustments to reconcile net earnings (loss) to net cash used in
        operating activities:
            Depreciation and amortization                                           736,958              845,425
            Deferred income taxes                                                   (49,578)            (300,000)
            Changes in assets and liabilities:
                Accounts receivable                                                 233,157              (76,272)
                Inventories                                                        (859,552)            (646,703)
                Prepaid expenses and other current assets                           (50,997)            (167,031)
                Accounts payable and accrued liabilities                          1,138,803               31,634
                Advances on contracts in progress                                   325,576           (1,267,338)
                                                                                -----------          -----------
                     Net cash used in operating activities                         (619,096)              (3,388)
                                                                                -----------          -----------

Cash flows from investing activities:
    Additions to property and equipment                                            (713,810)            (611,724)
    Increase in patent costs                                                        (19,924)             (29,370)
    Increase in software production costs                                                --              (34,229)
    Other assets                                                                      3,533              210,143
                                                                                -----------          -----------
                 Net cash used in investing activities                             (730,201)            (465,180)
                                                                                -----------          -----------

Cash flows from financing activities:
    Tax benefit of disqualifying dispositions of stock option exercises                  --              377,763
    Exercise of stock options                                                       135,414              542,981
    Repurchase of common stock                                                           --              (20,625)
                                                                                -----------          -----------
                      Net cash provided by financing activities                     135,414             (900,119)
                                                                                -----------          -----------

Net increase (decrease) in cash and cash equivalents                             (1,213,883)             431,551

Cash and cash equivalents, beginning of period                                    1,695,727              970,997
                                                                                -----------          -----------
Cash and cash equivalents, end of period                                        $   481,844          $ 1,402,548
                                                                                ===========          ===========

Supplemental disclosures of cash flow information:
        Cash paid during the year for:
            Interest expense                                                    $     2,810          $     5,118
                                                                                ===========          ===========
            Income taxes                                                        $    44,400          $    75,895
                                                                                ===========          ===========
</TABLE>

     See accompanying notes to condensed consolidated financial statements.

                                       5
<PAGE>   6


                        SPIRE CORPORATION AND SUBSIDIARY
              NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS

                               September 30, 1998


(1)    INTERIM FINANCIAL STATEMENTS

             In the opinion of management, the accompanying unaudited condensed
       consolidated financial statements contain all adjustments necessary to
       fairly present the Company's financial position as of September 30, 1998,
       the results of operations for the three and nine months ended September
       30, 1998 and 1997, and changes in cash flows for the nine months ended
       September 30, 1998 and 1997. The results of operations for the nine
       months ended September 30, 1998 are not necessarily indicative of the
       results to be expected for the fiscal year ending December 31, 1998.
       Certain amounts from the second quarter 1998 financial statements have
       been reclassified to conform to the third quarter 1998 presentation.

             The accounting policies followed by the Company are set forth in
       Note 2 to the Company's consolidated financial statements in its annual
       report on Form 10-KSB for the year ended December 31, 1997.

             The financial statements, with the exception of the December 31,
       1997 balance sheet, are unaudited and have not been examined by
       independent certified public accountants.


(2)    INVENTORIES

             Inventories consist of the following:

                                                September 30,      December 31,
                                                    1998               1997
                                                -------------      ------------

             Raw materials                       $  790,521          $736,930
             Work in process                      1,057,611           251,650
                                                 ----------          --------
                                                 $1,848,132          $988,580
                                                 ==========          ========

(3)    EARNINGS PER SHARE

             The reconciliation of the denominators of the basic and diluted
       earnings (loss) per share computations for the Company's reported
       earnings (loss) is as follows:

<TABLE>
<CAPTION>
                                                       Three Months Ended                Nine Months Ended
                                                          September 30,                    September 30,
                                                   --------------------------        --------------------------
                                                      1998             1997             1998             1997
                                                   ---------        ---------        ---------        ---------

      <S>                                          <C>              <C>              <C>              <C>      
      Weighted average number of shares
          outstanding - basic                      3,243,766        3,094,744        3,232,722        3,052,263
      Incremental shares from the assumed
          exercise of stock options                       --          222,884               --          222,884
                                                   ---------        ---------        ---------        ---------
      Weighted average number of shares
          outstanding - diluted                    3,243,766        3,317,628        3,232,722        3,275,147
                                                   =========        =========        =========        =========
</TABLE>



                                       6

<PAGE>   7



ITEM 2.  MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS
         OF OPERATIONS 

OVERVIEW

       Spire develops, manufactures and markets highly-engineered photovoltaic
module manufacturing equipment and optoelectronic products and provides
biomedical processing services. Spire is the world's leader in the design and
manufacture of specialized equipment for the production of terrestrial
photovoltaic modules from solar cells, with its equipment installed in 140
factories and in 38 countries. The Company also offers certain optoelectronic
products and is continuing to develop additional advanced optoelectronic
products for telecommunications, biomedical and electronics applications,
including solar cells used to power satellites. Spire's value-added biomedical
processing services offer surface treatments to enhance the durability or the
antimicrobial characteristics of orthopedic and other medical devices.

       The Company's net sales and revenues for the quarter ended September 30,
1998 declined, compared to the quarter ended September 30, 1997.

RESULTS OF OPERATIONS

       The following table sets forth certain items as a percentage of net sales
and revenues for the periods presented:

<TABLE>
<CAPTION>
                                                             Three Months Ended             Nine Months Ended
                                                                September 30,                 September 30,
                                                            --------------------          ---------------------
                                                             1998           1997           1998            1997
                                                            -----          -----          -----           -----

       <S>                                                  <C>            <C>            <C>             <C>   
       Net sales and revenues                               100.0%         100.0%         100.0%          100.0%
       Cost of sales and revenues                            71.5           64.4           75.5            65.1
                                                            -----          -----          -----           -----
       Gross profit                                          28.5           35.6           24.5            34.9
       Selling, general and administrative expenses          37.5           24.1           42.6            25.1
                                                            -----          -----          -----           -----
       Earnings (loss) from operations                       (9.0)          11.5          (18.1)            9.8
       Earnings (loss) before income taxes                   (9.0)          11.7          (18.0)            9.8
       Income tax expense                                      --             --             --             0.6
                                                            -----          -----          -----           -----
       Net (loss) earnings                                   (9.0%)          11.7%        (18.0%)           9.2%
                                                            =====          ======         ======          =====
</TABLE>


THREE AND NINE MONTHS ENDED SEPTEMBER 30, 1998 COMPARED TO THREE AND NINE MONTHS
ENDED SEPTEMBER 30, 1997

Net Sales and Revenues

       Net sales and revenues decreased $2,456,000 or 40% for the three months
ended September 30, 1998 to $3,720,000, compared to $6,176,000 for the three
months ended September 30, 1997. Contract research, service and license revenues
decreased $964,000 or 25% to $2,869,000 for the three months ended September 30,
1998 compared to $3,833,000 for 1997. Manufacturing equipment sales decreased
$1,492,000 or 64% to $851,000 for 1998, compared to $2,343,000 for 1997. The
following table categorizes the Company's net sales and revenues for the periods
presented:
<TABLE>
<CAPTION>
                                                                     Three Months Ended September 30,
                                                              ----------------------------------------------
                                                                 1998              1997             % Change
                                                              ----------        ----------          --------

       <S>                                                    <C>               <C>                   <C>  
       Contract research, service and license revenues        $2,869,000        $3,833,000            (25%)
       Manufacturing equipment sales                             851,000         2,343,000            (64%)
                                                              ----------        ----------
       Net sales and revenues                                 $3,720,000        $6,176,000            (40%)
                                                              ==========        ==========
</TABLE>


                                       7



<PAGE>   8

       Net sales and revenues decreased $5,452,000 or 32% for the nine months
ended September 30, 1998 to $11,608,000, compared to $17,060,000 for the nine
months ended September 30, 1997. Contract research, service and license revenues
decreased $2,169,000 or 20% to $8,605,000 for the nine months ended September
30, 1998 compared to $10,774,000 for 1997. Manufacturing equipment sales
decreased $3,283,000 or 52% to $3,003,000 for 1998, compared to $6,286,000 for
1997.

       The following table categorizes the Company's net sales and revenues for
the periods presented:

<TABLE>
<CAPTION>
                                                                      Nine Months Ended September 30,
                                                               --------------------------------------------
                                                                   1998              1997          % Change
                                                               -----------       -----------       --------

       <S>                                                     <C>               <C>                 <C>  
       Contract research, service and license revenues         $ 8,605,000       $10,774,000         (20%)
       Manufacturing equipment sales                             3,003,000         6,286,000         (52%)
                                                               -----------       -----------
       Net sales and revenues                                  $11,608,000       $17,060,000         (32%)
                                                               ===========       ===========
</TABLE>

       The decline in manufacturing equipment sales for the three and nine month
periods ended September 30, 1998 is primarily due to a global decline in
photovoltaic module production. The decline in contract research, service and
license revenues for the three and nine month periods ended September 30, 1998
is primarily due to a decline in government contracts in 1998. The decline in
contract research, service and license revenues for the nine month periods ended
September 30, 1998 is also due to revenue of $600,000 associated with a one-time
technology transfer in the second quarter of 1997, and a revision to government
contract overhead rates for 1997 and 1998, which came in lower than billed rates
and resulted in a reserve of $70,000 in the second quarter of 1998.

Cost of Sales and Revenues

       The cost of sales and revenues decreased $1,314,000 to $2,661,000, but
increased to 72% of net sales and revenues, for the quarter ended September 30,
1998, compared to $3,975,000 or 64% of net sales and revenues for the quarter
ended September 30, 1997.

       The cost of contract research, service and license revenues decreased
$679,000 to $1,698,000, and decreased to 59% of related revenues, for the
quarter ended September 30, 1998, compared to $2,377,000 or 62% of related
revenues for the quarter ended September 30, 1997. Cost of manufacturing
equipment sales decreased $635,000 to $963,000, but increased to 113% of related
sales, for the quarter ended September 30, 1998, compared to $1,598,000 or 68%
of related sales, for the quarter ended September 30, 1997.

       The following table categorizes the Company's cost of sales and revenues
for the periods presented, stated in dollars and as a percentage of related
sales and revenues:
<TABLE>
<CAPTION>
                                                                              Three Months Ended September 30,
                                                                    -----------------------------------------------------
                                                                       1998             %            1997              %
                                                                    ----------         ---         ----------         ---

       <S>                                                          <C>                <C>         <C>                 <C>
       Contract research, service and license revenues              $1,698,000          59%        $2,377,000          62%
       Manufacturing equipment sales                                   963,000         113%         1,598,000          68%
                                                                    ----------                     ----------
       Total cost of sales and revenues                             $2,661,000          72%        $3,975,000          64%
                                                                    ==========                     ==========
</TABLE>

       The cost of sales and revenues decreased $2,349,000 to $8,764,000, but
increased to 75% of net sales and revenues, for the nine months ended September
30, 1998, compared to $11,112,000 or 65% of net sales and revenues for the nine
months ended September 30, 1997.

       The cost of contract research, service and license revenues decreased
$841,000 to $6,058,000, but increased to 70% of related revenues, for the nine
months ended September 30, 1998, compared to $6,899,000 or 64% of related
revenues for the nine months ended September 30, 1997. Cost of manufacturing
equipment sales decreased $1,508,000 to $2,705,000, but increased to 90% of
related sales, for the nine months ended September 30, 1998, compared to
$4,213,000 or 67% of related sales, for the nine months ended September 30,
1997.


                                       8



<PAGE>   9

       The following table categorizes the Company's cost of sales and revenues
for the periods presented, stated in dollars and as a percentage of related
sales and revenues:
<TABLE>
<CAPTION>
                                                                                Nine Months Ended September 30,
                                                                    -----------------------------------------------------
                                                                       1998             %             1997             %
                                                                    ----------         ---         -----------        ---

       <S>                                                          <C>                 <C>        <C>                 <C>
       Contract research, service and license revenues              $6,058,000          70%        $ 6,899,000         64%
       Manufacturing equipment sales                                 2,706,000          90%          4,213,000         67%
                                                                    ----------                     -----------
       Total cost of sales and revenues                             $8,764,000          75%        $11,112,000         65%
                                                                    ==========                     ===========
</TABLE>

       For both the three and nine month periods ended September 30, 1998, the
increase in total cost of sales and revenues as a percentage of related sales
and revenues is due to lower sales volume in 1998 available to spread fixed cost
of sales over and a change in product mix from 1997, particularly related to a
technology transfer in the second quarter of 1997 for which revenue of $600,000
was recognized.

Selling, General and Administrative Expenses

       Selling, general and administrative expenses for the nine months ended
September 30, 1998 increased $665,000 to $4,949,000, and increased to 43% of
sales and revenues, compared to $4,284,000 or 25% of sales and revenues for the
nine months ended September 30, 1997. Selling, general and administrative
expenses increased due to the accrual of $547,000 of non-recurring costs in the
second quarter of 1998 related to the settlement with the government (See Part
II, Item 1. Legal Proceedings). Also impacting selling, general and
administrative expenses was an increase in legal costs for the nine months ended
September 30, 1998 versus the similar 1997 time period.

       Selling, general and administrative expenses for the quarter ended
September 30, 1998 decreased $90,000 to $1,396,000, but increased to 38% of
sales and revenues, compared to $1,486,000 or 24% of sales and revenues for the
quarter ended September 30, 1997. The decrease in selling, general and
administrative expenses in the third quarter of 1998 versus the third quarter of
1997 was primarily due to a decrease in public relations and marketing expenses
and commissions in 1998. During the third quarter of 1998, the Company incurred
legal expenses of $140,000 in pursuit of a claim against a former employee.

 Depreciation and Amortization Expenses

       Depreciation and amortization expenses for the nine months ended
September 30, 1998 decreased $108,000 or 13% to $737,000, compared to $845,000
for the nine months ended September 30, 1997. Capital expenditures increased
$102,000 or 17% to $714,000 for the nine months ended September 30, 1998,
compared to $612,000 for the nine months ended September 30, 1997.

Interest

       The Company earned $3,000 in interest income for the quarter ended
September 30, 1998, compared to $10,000 for the quarter ended September 30,
1997. The Company incurred insignificant interest expense in both periods.

Income Taxes

       The Company recorded $9,000 income tax expense for the nine months ended
September 30, 1998 and income tax expense of $400,000 for the nine months ended
September 30, 1997. At September 30, 1998, the Company had gross deferred tax
assets of $349,578, which represents the amount of tax benefits of existing
deductible temporary differences or carryforwards that are more likely than not
to be realized through the generation of sufficient future taxable income within
the carryforward period.

Net Earnings (Loss)

       The Company reported a net loss for the quarter ended September 30, 1998
of $335,000, compared to net earnings of $725,000 for the quarter ended
September 30, 1997. The decline in the Company's profitability resulted in large
part 




                                       9



<PAGE>   10

from an approximately $2,500,000 decrease in net sales and revenues when
compared with the prior period, and to a lesser extent, an increase in legal
costs in the third quarter of 1998 versus the third quarter of 1997.

LIQUIDITY AND CAPITAL RESOURCES

       To date the Company has been able to fund its liquidity requirements
using cash from operations and available lines of credit. On April 7, 1998, the
Company amended and extended its revolving credit agreement with Silicon Valley
Bank. This agreement provides for a $2 million revolving credit facility, based
upon eligible accounts receivable requirements. This line of credit has been
established to provide the Company with resources for general working capital
purposes and Standby Letter of Credit Guarantees for foreign customers. The line
is secured by all assets of the Company. Interest on the line is at the Bank's
prime rate plus one-half of one percent. The line contains covenants including
provisions relating to profitability and net worth. As of September 30, 1998,
the Company was in default of certain financial covenants; however the Company
anticipates receiving a waiver of these defaults from the Bank. As of September
30, 1998, the Company had no outstanding debt under this revolving credit
facility. The Company has also entered into a $1 million equipment leasing line
with Silicon Valley Bank.

       The Company believes it has sufficient resources to finance its current
operations for the foreseeable future through working capital, its existing line
of credit and available lease arrangements. In addition, the Company has taken
steps to conserve its resources by reducing its cost of operations. Cash and
cash equivalents decreased $1,214,000 to $482,000 at September 30, 1998, from
$1,696,000 at December 31, 1997. To date there are no material commitments by
the Company for capital expenditures. At September 30, 1998, the Company's
accumulated deficit was $461,000, compared to retained earnings of $1,632,000 as
of December 31, 1997. Working capital as of September 30, 1998 decreased 39% to
$3,026,000, compared to $4,977,000 as of December 31, 1997.

RECENT ACCOUNTING PRONOUNCEMENTS

       In June 1997, the Financial Accounting Standards Board issued SFAS 131,
"Disclosures about Segments of an Enterprise and Related Information," which
establishes standards for the way that public business enterprises report
selected information about operating segments in annual financial statements and
requires that those enterprises report selected information about operating
segments in interim financial reports to stockholders. It also establishes
standards for related disclosures about products and services, geographic areas
and major customers. SFAS 131, which becomes effective for the Company in its
year ending December 31, 1998, is not expected to have a material impact on the
Company's results of operations. The Company is in the process of determining
the impact of SFAS 131 on its footnote disclosures.

       In March 1998, the American Institute of Certified Public Accountants
issued Statement of Position 98-1, "Accounting for the Costs of Computer
Software Developed or Obtained for Internal Use" (SOP 98-1), which establishes
guidelines for the accounting for the costs of all computer software developed
or obtained for internal use. SOP 98-1 is effective for the Company in 1999 and
is not expected to have a material effect on the Company's financial statements.

       In June 1998, the Financial Accounting Standards Board issued Statement
of Financial Accounting Standards ("SFAS") No. 133, Accounting for Derivative
Instruments and Hedging Activities, which establishes accounting and reporting
standards for derivative instruments, including certain derivative instruments
embedded in other contracts (collectively referred to as "derivatives") and for
hedging activities. This statement requires that an entity recognize all
derivatives as either assets or liabilities in the balance sheet and measure
those instruments at fair value. The statement also sets forth the criteria for
determining whether a derivative may be specifically designed as a hedge of a
particular exposure with the intent of measuring the effectiveness of that hedge
in the statement of operations. SFAS No. 133 is effective for all fiscal
quarters of fiscal years beginning after June 15, 1999. Management does not
believe that the adoption of this statement will have a material impact on the
Company's consolidated financial position, results of operations or cash flows.

IMPACT OF THE YEAR 2000 ISSUE

       The Company has initiated a program to identify the potential impact of
the Year 2000 issue. The Year 2000 relates to computer programs and embedded
computer chips being viable to distinguish between the year 1900 and the year
2000.



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<PAGE>   11

       The Company is near completion of a review and assessment of potentially
affected items, including information technology and non-information technology,
for Year 2000 compliance. A final examination of potentially affected items will
be completed no later than December 1998. When identifying computer programs
that are not Year 2000 compliant, the Company has sought to upgrade these
programs to newer versions of software that are Year 2000 compliant. The Company
estimates that it will obtain all required software no later than June 1999. The
cost of the software is estimated to not exceed $50,000.

       The Company's business is also dependent upon systems of third parties,
primarily its vendors and customers. The Company has prepared questionnaires and
submitted them to all of its significant vendors. The Company is now collecting
and analyzing their responses. Although this process is incomplete, no known
problems have been identified. The Company expects to complete the analysis by
March 1999. During the fourth quarter of 1998, the Company will be issuing
questionnaires to its customer base. The Company anticipates completion of the
analysis of its customer base by March 1999.

       The Company believes that its most likely and reasonable worst case
scenario relating to the Year 2000 would be failure of certain of its
applications with imbedded software or failure of such applications of a
material customer or vendor. Failure of applications of embedded software could
result in a disruption of the Company's operation and thereby negatively affect
revenues and profitability. Failure of a significant vendor's information
systems could temporarily interrupt supply of materials or services and impair
the Company's ability to fill orders. If a major customer system fails to become
Year 2000 compliant, the Company's revenues could be temporarily disrupted if
the customer suspends further purchases. Although there can be no assurance that
these failures will not have an adverse effect on the Company's business, the
Company believes that any such adverse effect would not be material.

       The Company is formulating contingency plans to address any such
failures. The plans include identifying Year 2000 compliant software for the
Company's internal systems, and identifying alternative vendors to assure
continuity of supplies.

       THE FOREGOING STATEMENTS MAY INCLUDE FORWARD-LOOKING STATEMENTS SUBJECT
TO RISKS AND UNCERTAINTIES THAT COULD CAUSE ACTUAL RESULTS TO DIFFER MATERIALLY
FROM THOSE INDICATED IN THE FORWARD-LOOKING STATEMENTS. FACTORS THAT MIGHT CAUSE
SUCH A DIFFERENCE INCLUDE, BUT ARE NOT LIMITED TO, THOSE DISCUSSED OR REFERRED
TO IN THIS REPORT AND IN ITEM 6 OF THE ANNUAL REPORT ON FORM 10-KSB FOR THE YEAR
ENDED DECEMBER 31, 1997.


PART II - OTHER INFORMATION


ITEM 1.  LEGAL PROCEEDINGS

       On March 2, 1998 the Company received a letter from the Office of the
United States Attorney for the Eastern District of Virginia stating that it was
considering the commencement of a civil action concerning research initiatives
undertaken by the Company in the period from 1990 to 1997. The letter alleged
that, in certain instances, the Company had failed to inform the government of
pending or previously submitted proposals for work the government alleges was
related to proposals which were funded. Rather than continuing to incur the
legal costs and expend management resources in litigating this matter the
Company settled with the government on August 18, 1998 for $547,000. This matter
was previously reported in Quarterly Reports on Form 10-QSB for quarterly
periods ended March 31, 1998 and June 30, 1998.

ITEM 6.  EXHIBITS AND REPORTS ON FORM 8-K

A.     The following exhibits are filed herewith:

       27    Financial Data Schedule

B.     During the quarter ended September 30, 1998, the Company filed no reports
       on Form 8-K.


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<PAGE>   12



                                   SIGNATURES


In accordance with the requirements of the Exchange Act, the registrant caused
this report to be signed on its behalf by the undersigned, thereunto duly
authorized.


                                    SPIRE CORPORATION
                                    (Registrant)


    12 NOVEMBER 1998                By: /s/ Roger G. Little
-----------------------------           ----------------------------------------
Date                                    Roger G. Little
                                        President, Chief Executive Officer and 
                                        Chairman of the Board


    12 NOVEMBER 1998                By: /s/ Richard S. Gregorio
-----------------------------           ----------------------------------------
Date                                    Richard S. Gregorio
                                        Vice President and Chief Financial 
                                        Officer, Treasurer, Clerk and
                                        Principal Accounting Officer




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