QUARTERLY REPORT ON FORM 10-Q
                     U.S. SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON D.C. 20549
                            _________________________

(Mark One)
[ X ] QUARTERLY REPORT UNDER SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE  ACT
      OF 1934
      For the quarterly period ended September 26, 1999

                                       or

[   ] TRANSITION  REPORT  PURSUANT  TO SECTION 13 OR  15(d)  OF  THE  SECURITIES
      EXCHANGE ACT OF 1934
      For the transition period from _____________to_____________


                         Commission File Number: 1-12432


                      AMERICAN POWER CONVERSION CORPORATION
             (Exact name of Registrant as specified in its charter)


             MASSACHUSETTS                              04-2722013
    (State or other jurisdiction of         (I.R.S. employer identification no.)
     incorporation or organization)


             132 FAIRGROUNDS ROAD, WEST KINGSTON, RHODE ISLAND 02892
                                  401-789-5735
          (Address and telephone number of principal executive offices)


Indicate  by check mark whether the Registrant (1) has filed all reports  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  [   ]

  Registrant's Common Stock outstanding, $.01 par value, at November 5, 1999 -
                               192,595,000 shares

                                 1
<PAGE>
                                                                       FORM 10-Q
                                                              September 26, 1999


             AMERICAN POWER CONVERSION CORPORATION AND SUBSIDIARIES

                                     INDEX
                                                                    Page No.
Part I - Financial Information:

Item 1.  Consolidated Condensed Financial Statements:
         Consolidated Condensed Balance Sheets -
         September 26, 1999 (Unaudited) and December 31, 1998        3 - 4

         Consolidated Condensed Statements of Income -
         Three Months and Nine Months Ended
         September 26, 1999 and September 27, 1998 (Unaudited)         5

         Consolidated Condensed Statements of Cash Flows -
         Three Months and Nine Months Ended
         September 26, 1999 and September 27, 1998 (Unaudited)         6

         Notes to Consolidated Condensed Financial Statements
         (Unaudited)                                                 7 - 8

Item 2.  Management's Discussion and Analysis of Financial
         Condition and Results of Operations                         9 - 14

Item 3.  Quantitative and Qualitative Disclosures About Market Risk    14


Part II - Other Information:

Item 1.  Legal Proceedings                                             15

Item 6.  Exhibits and Reports on Form 8-K                              15


Signatures                                                             16

Exhibit Index                                                          17

                                2
<PAGE>
                                                                       FORM 10-Q
                                                              September 26, 1999
PART I - CONSOLIDATED CONDENSED FINANCIAL STATEMENTS

ITEM 1 - FINANCIAL STATEMENTS
<TABLE>
             AMERICAN POWER CONVERSION CORPORATION AND SUBSIDIARIES
                      CONSOLIDATED CONDENSED BALANCE SHEETS
                                 (In thousands)

                                     ASSETS
<CAPTION>
                                                        September 26,           December 31,
                                                                1999                   1998
                                                         (Unaudited)
<S>                                                         <C>                    <C>

Current assets:
Cash and cash equivalents                                   $330,920               $219,908
Accounts receivable,
 less allowance for doubtful accounts of
 $20,716 in 1999 and $15,471 in 1998                         241,431                180,356
Inventories:
 Raw materials                                                72,241                 87,975
 Work-in-process and finished goods                          126,347                140,707
Total inventories                                            198,588                228,682

Prepaid expenses and other current assets                     18,996                 17,801

Deferred income taxes                                         28,296                 28,498

Total current assets                                         818,231                675,245

Property, plant and equipment:
 Land, buildings and improvements                             56,714                 51,735
 Machinery and equipment                                     129,405                125,274
 Office equipment, furniture, and fixtures                    52,084                 44,955
 Purchased software                                           16,862                 11,505

                                                             255,065                233,469

Less accumulated depreciation and amortization               101,811                 85,205

Net property, plant, and equipment                           153,254                148,264

Goodwill and other intangibles                                49,008                 45,837

Other assets                                                   2,108                  2,637


Total assets                                              $1,022,601               $871,983
</TABLE>

See accompanying notes to consolidated condensed financial statements.

                               3
<PAGE>
                                                                       FORM 10-Q
                                                              September 26, 1999
<TABLE>
             AMERICAN POWER CONVERSION CORPORATION AND SUBSIDIARIES
                CONSOLIDATED CONDENSED BALANCE SHEETS (CONTINUED)
                                 (In thousands)

                      LIABILITIES AND SHAREHOLDERS' EQUITY

<CAPTION>
                                                        September 26,           December 31,
                                                                1999                   1998
                                                         (Unaudited)
<S>                                                          <C>                    <C>
Current liabilities:
Short term debt                                              $   160                $12,540
Accounts payable                                              83,831                 75,190
Accrued expenses                                              41,244                 28,560
Accrued compensation                                          26,208                 22,130
Accrued sales and marketing programs                          14,180                 17,824
Accrued retirement contributions                               3,584                  2,469
Income taxes payable                                          21,553                 22,753

Total current liabilities                                    190,760                181,466

Deferred tax liability                                         5,082                  7,500

Total liabilities                                            195,842                188,966

Minority interest                                                  -                  1,725

Shareholders' equity:
Common stock, $.01 par value;
 authorized 200,000 shares; issued 192,680
 shares in 1999 and 191,946 shares in 1998                     1,927                    960
Additional paid-in capital                                    73,040                 67,080
Retained earnings                                            754,033                614,301
Treasury stock, 250 shares, at cost                           (1,551)                (1,551)
Accumulated other comprehensive income (loss)                   (690)                   502

Total shareholders' equity                                   826,759                681,292

Total liabilities and shareholders' equity                $1,022,601               $871,983
</TABLE>

See accompanying notes to consolidated condensed financial statements.

                               4
<PAGE>
                                                                       FORM 10-Q
                                                              September 26, 1999
<TABLE>
             AMERICAN POWER CONVERSION CORPORATION AND SUBSIDIARIES
                   CONSOLIDATED CONDENSED STATEMENTS OF INCOME
                    (In thousands except earnings per share)
<CAPTION>
                                                      Nine months ended          Three months ended
                                                September 26, September 27, September 26, September 27,
                                                        1999          1998          1999          1998
                                                                       (Unaudited)

<S>                                                 <C>           <C>           <C>           <C>
Net sales                                           $948,567      $806,898      $355,920      $327,370

Cost of goods sold                                   520,922       446,385       188,983       183,087

Gross profit                                         427,645       360,513       166,937       144,283

Operating expenses:
Marketing, selling, general and administrative       211,451       189,750        74,025        70,841
Research and development                              25,951        24,658         8,176         7,962
Acquired research and development                          -         7,554             -           167

Total operating expenses                             237,402       221,962        82,201        78,970

Operating income                                     190,243       138,551        84,736        65,313

Other income, net                                      7,959         9,128         3,388         2,149

Earnings before income taxes
  and minority interest                              198,202       147,679        88,124        67,462

Income taxes                                          58,470        47,340        25,997        20,621

Earnings before minority interest                    139,732       100,339        62,127        46,841

Minority interest, net                                     -           223             -           223

Net income                                          $139,732      $100,116      $ 62,127      $ 46,618

Basic earnings per share                             $   .73       $   .52       $   .32       $   .24

Basic weighted average shares outstanding            191,998       190,824       192,272       191,074

Diluted earnings per share                           $   .71       $   .52       $   .32       $   .24

Diluted weighted average shares outstanding          195,926       193,294       196,621       193,722
</TABLE>

See accompanying notes to consolidated condensed financial statements.

                                5
<PAGE>
                                                                       FORM 10-Q
                                                              September 26, 1999
<TABLE>
             AMERICAN POWER CONVERSION CORPORATION AND SUBSIDIARIES
                 CONSOLIDATED CONDENSED STATEMENTS OF CASH FLOWS
                                 (In thousands)
<CAPTION>
                                                      Nine months ended          Three months ended
                                                September 26, September 27, September 26, September 27,
                                                        1999          1998          1999          1998
                                                                       (Unaudited)
<S>                                                 <C>           <C>            <C>           <C>
Cash flows from operating activities
Net income                                          $139,732      $100,116       $62,127       $46,618
Adjustments to reconcile net income to net cash
provided by operating activities:
Depreciation and amortization                         19,237        18,134         7,117         6,391
Gain on sale of property, plant and equipment           (277)            -          (277)            -
Provision for doubtful accounts                        5,125         6,295         1,661         3,697
Deferred income taxes                                 (2,216)       (4,479)        2,059        (1,247)
Acquired research and development                          -         7,554             -           167
Changes in operating assets and liabilities
excluding effects of acquisition:
  Accounts receivable                                (66,200)      (54,508)      (47,771)      (19,179)
  Inventories                                         30,094       (99,567)       33,308       (23,145)
  Prepaid expenses and other current assets           (1,195)       (6,392)        4,467        (2,273)
  Other assets                                           529        (1,549)          132        (1,234)
  Accounts payable                                     8,641        54,406         1,235         4,476
  Accrued expenses                                    14,233         8,609         1,526         8,987
  Income taxes payable                                (1,200)       10,885        (3,066)        8,482
  Other, net                                          (1,266)          (38)          510           (38)
Net cash provided by operating activities            145,237        39,466        63,028        31,702

Cash flows from investing activities
Capital expenditures, net of capital grants          (21,562)      (43,321)       (7,658)      (19,147)
Proceeds from sale of property, plant and equipment    1,100             -         1,100             -
Acquisition                                           (8,310)      (53,714)            -        (1,185)
Net cash used in investing activities                (28,772)      (97,035)       (6,558)      (20,332)

Cash flows from financing activities
Repayment of short term debt                         (12,380)       (9,803)         (848)       (9,803)
Proceeds from issuances of common stock                6,927         6,095         3,479         3,980
Net cash (used in) provided by financing activities   (5,453)       (3,708)        2,631        (5,823)

Net change in cash and cash equivalents              111,012       (61,277)       59,101         5,547
Cash and cash equivalents at beginning of period     219,908       270,134       271,819       203,310
Cash and cash equivalents at end of period          $330,920      $208,857      $330,920      $208,857

Supplemental cash flow disclosures
Cash paid during the period for income taxes
 (net of refunds)                                    $58,664       $36,301       $26,399       $12,139
Details of acquisition:
 Fair value of assets                                $ 8,310      $105,517        $    -        $  973
 Liabilities and minority interest                         -       (49,843)            -           212
 Cash paid                                             8,310        55,674             -         1,185
 Cash acquired                                             -        (1,960)            -             -
 Acquisition                                         $ 8,310      $ 53,714        $    -        $1,185
</TABLE>

See accompanying notes to consolidated condensed financial statements.

                                6
<PAGE>
                                                                       FORM 10-Q
                                                              September 26, 1999



             AMERICAN POWER CONVERSION CORPORATION AND SUBSIDIARIES
              NOTES TO CONSOLIDATED CONDENSED FINANCIAL STATEMENTS
                                   (Unaudited)


1.   Management Representation

In  the  opinion  of  management, the accompanying unaudited  interim  financial
statements  contain  all  adjustments  (consisting  of  only  normal   recurring
accruals) necessary to present fairly the financial position and the results  of
operations  for the interim periods.  The results of operations for the  interim
periods  are not necessarily indicative of results to be expected for  the  full
year.


2.   Principles of Consolidation

The  consolidated  financial  statements include  the  financial  statements  of
American  Power  Conversion Corporation and its wholly-owned subsidiaries.   All
intercompany accounts and transactions are eliminated in consolidation.


3.   Per Share Data

Basic  earnings  per share is computed by dividing net income  by  the  weighted
average number of common shares outstanding during the period.  Diluted earnings
per  share is computed by dividing net income by the weighted average number  of
common  shares  and  dilutive  potential common  shares  (i.e.,  stock  options)
outstanding  during  the period.  Under the treasury stock  method,  unexercised
options  are  assumed  to be exercised at the beginning  of  the  period  or  at
issuance,  if  later.   The assumed proceeds are then used  to  purchase  common
shares  at the average market price during the period.  Potential common  shares
for  which  inclusion would have the effect of increasing diluted  earnings  per
share (i.e., antidilutive) are excluded from the computation.
<TABLE>
<CAPTION>
In thousands                                              Nine months ended          Three months ended
                                                    September 26, September 27, September 26, September 27,
                                                            1999          1998          1999          1998
<S>                                                      <C>           <C>           <C>           <C>
Basic weighted average
 shares outstanding                                      191,998       190,824       192,272       191,074
Net effect of dilutive potential common
 shares outstanding based on the
 treasury stock method using the
 average market price                                      3,928         2,470         4,349         2,648
Diluted weighted average
 shares outstanding                                      195,926       193,294       196,621       193,722

Antidilutive potential common shares
 excluded from the computation above                         725         2,045           260         2,111

Shares data reflect a two-for-one stock split effected May 28, 1999.
</TABLE>

                                7
<PAGE>
4.   Shareholders' Equity

Stock Split
The  Company  effected a two-for-one stock split in the form  of  a  100%  stock
dividend payable on May 28, 1999 to shareholders of record on May 7, 1999.   All
share   and  per  share  amounts  in  the  accompanying  consolidated  financial
statements have been restated to give effect to this stock split.

After giving effect to the May 1999 stock split, changes in paid-in capital  for
the  periods  presented represent issuances of common stock resulting  from  the
exercise of employee stock options.


5.   Comprehensive Income

The components of comprehensive income, net of tax, are as follows:
<TABLE>
<CAPTION>
In thousands                                           Nine months ended          Three months ended
                                                 September 26, September 27, September 26, September 27,
                                                         1999          1998          1999          1998
<S>                                                  <C>           <C>            <C>           <C>
Net income                                           $139,732      $100,116       $62,127       $46,618

Other comprehensive income (loss), net of tax:
 Change in foreign currency
  translation adjustment                               (1,192)         (189)          510          (189)
Other comprehensive income (loss)                      (1,192)         (189)          510          (189)

Comprehensive income                                 $138,540      $ 99,927       $62,637       $46,429
</TABLE>

6.   Operating Segment Information

Basis for presentation
The  Company's  operating  businesses  design,  manufacture,  and  market  power
protection  equipment  and  related software and accessories  for  computer  and
computer-related  equipment.  The Company manages its businesses  based  on  the
nature   of   products  provided.   These  businesses  share  similar   economic
characteristics and have been aggregated into one reportable operating  segment.
The  Company  evaluates  the  performance of  its  businesses  based  on  direct
contribution   margin.   Direct  contribution  margin  includes   research   and
development   ("R&D"),   marketing,   and   administrative   expenses   directly
attributable  to  the segment and excludes certain expenses  which  are  managed
outside the reportable segment.  Costs excluded from segment profit are indirect
operating expenses, primarily consisting of selling and corporate expenses,  and
income  taxes.  Expenditures for additions to long-lived assets are not reported
to management by the operating businesses.

Summary operating segment information is as follows:
<TABLE>
<CAPTION>
In thousands                                              Nine months ended          Three months ended
                                                    September 26, September 27, September 26, September 27,
                                                            1999          1998          1999          1998
<S>                                                     <C>           <C>           <C>           <C>
Net sales                                               $948,567      $806,898      $355,920      $327,370

Segment direct contribution margin                      $396,094      $314,095      $156,052      $127,426
Indirect operating expenses                              205,851       175,544        71,316        62,113
Other income, net                                          7,959         9,128         3,388         2,149
Earnings before income taxes and
 minority interest                                      $198,202      $147,679       $88,124       $67,462
</TABLE>
                                8
<PAGE>
ITEM 2.   MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL
          CONDITION AND RESULTS OF OPERATIONS

RESULTS OF OPERATIONS:

Revenues

Net sales were $355.9 million for the third quarter of 1999, an increase of 8.7%
compared to $327.4 million for the same period in 1998.  Net sales for the first
nine  months of 1999 were $948.6 million compared to $806.9 million in 1998,  an
increase  of  17.6%.  The increases were attributable to strong demand  for  the
Company's  products  across  all  solution  applications,  combined  with  sales
attributable to Silcon A/S ("Silcon") (see "Acquisition" below).  Third  quarter
and  year-to-date 1999 net sales growth was led by increases in Asia and Europe.
For  the quarter and year-to-date periods, the Asia Pacific region grew 42%  and
48%,  respectively,  EMEA (Europe, Middle East and Africa)  grew  16%  and  35%,
respectively,  while  the Americas (North and Latin America)  grew  1%  and  7%,
respectively.  International net sales (excluding Canada) comprised 39% and  37%
of total net sales in the third quarters of 1999 and 1998, respectively, and 41%
and  37%  of total net sales in the first nine month periods of 1999  and  1998,
respectively.

Cost of Goods Sold

Cost of goods sold was $189.0 million or 53.1% of net sales in the third quarter
of  1999 compared to $183.1 million or 55.9% in the third quarter of 1998.  Cost
of  goods sold was $520.9 million or 54.9% of net sales in the first nine months
of  1999  compared to $446.4 million or 55.3% in the first nine months of  1998.
Third  quarter  1999  gross margin was 46.9% of sales, approximately  280  basis
points  higher than the comparable period in 1998.  Gross margin for  the  first
nine  month  period of 1999 was 45.1% of sales, approximately  40  basis  points
higher  than  the  comparable  period in 1998.   The  improvements  were  driven
primarily  by the ongoing transition of production from the U.S. and Ireland  to
the  Philippines, improved capacity utilization associated with the  closure  of
the Company's manufacturing facility in Fort Meyers, Florida, and volume related
margin  improvements in Silcon and Symmetra products.  Total inventory  reserves
at  September 26, 1999 were $14.7 million compared to $13.3 million at  December
31,  1998.  The Company's reserve estimate methodology involves quantifying  the
total  inventory position having potential loss exposure, reduced by  an  amount
reasonably forecasted to be sold, and adjusting its interim reserve provisioning
to cover the net loss exposure.

Operating Expenses

Operating  expenses  include  marketing,  selling,  general  and  administrative
(SG&A), and R&D expenses.

SG&A expenses were $74.0 million or 20.8% of net sales for the third quarter  of
1999  compared to $70.8 million or 21.6% of net sales for the third  quarter  of
1998.   SG&A  expenses were $211.5 million or 22.3% of net sales for  the  first
nine  months  of 1999 compared to $189.8 million or 23.5% of net sales  for  the
first nine months of 1998.  The increases in total spending over last year  were
due  primarily to increased advertising and promotional costs, as well as  costs
associated  with  increased  staffing and operating expenses  of  the  Company's
marketing  and administrative functions.  However, the decreases as a percentage
of  sales  from  1998 to 1999 were attributable to certain fixed  SG&A  expenses
spread  over a higher revenue base, as well as the Company's focused efforts  to
manage spending.  The allowance for doubtful accounts at September 26, 1999  was
7.9%  of  accounts receivable, unchanged from 7.9% at December  31,  1998.   The
Company   continues  to  experience  strong  collection  performance.   Accounts
receivable  balances  outstanding  over  60  days  represented  11.9%  of  total
receivables  at  September 26, 1999, up from 8.6% at December  31,  1998.   This
increase  reflects  a growing portion of the Company's business  originating  in
areas where longer payment terms are customary, including a growing contribution
from  international markets as well as large system enterprise  sales  primarily
associated with Silcon products, combined with higher balances over 60 days of
certain U.S. distribution accounts.

Write-offs of uncollectible accounts have historically represented less than  1%
of total receivable balances.  A majority of international customer balances are
covered by receivables insurance.

                                9
<PAGE>
R&D expenses were $8.2 million or 2.3% of net sales and $8.0 million or 2.4%  of
net  sales  for  the  third quarters of 1999 and 1998, respectively,  and  $26.0
million  or  2.7% of net sales and $24.7 million or 3.1% of net  sales  for  the
first  nine month periods of 1999 and 1998, respectively, excluding 1998 charges
of  $7.6  million for acquired R&D (see "Acquisition" below).  The increases  in
total  R&D  spending during 1999 over the comparable periods in  1998  primarily
reflects  increased  numbers  of  software  and  hardware  engineers  and  costs
associated with new product development and engineering support.  The  decreases
as  a  percentage of sales from 1998 to 1999 were attributable to certain  fixed
R&D expenses spread over a higher revenue base.

Other Income, Net and Income Taxes

Other   income   is  comprised  principally  of  interest  income,   which   was
substantially  higher  during the third quarter of 1999 compared  to  the  third
quarter  of  1998 due to higher average cash balances available  for  investment
during  the third quarter of 1999.  However, interest income for the first  nine
month  period  of 1999 was lower than the comparable period last  year,  as  the
third  quarter 1999 increase was more than offset by the impact of lower average
cash  balances  available  for investment during the first  half  of  1999,  due
largely  to  cash  used late in the second half of 1998 in  the  acquisition  of
Silcon (see "Acquisition" below).

The  Company's effective income tax rates were approximately 29.5% and 30.5% for
the  quarters and nine month periods ended September 26, 1999 and September  27,
1998,  respectively.   The decrease from last year is due to  the  expected  tax
savings from an increasing portion of taxable earnings being generated from  the
Company's  operations  in jurisdictions currently  having  a lower income tax
rate than the present  U.S.  statutory income tax rate.

LIQUIDITY AND CAPITAL RESOURCES

Working  capital  at  September 26, 1999 was $627.5 million compared  to  $493.8
million at December 31, 1998.  The Company has been able to increase its working
capital position as the result of continued strong operating results and despite
internally  financing the capital investment required to expand its  operations.
The  Company's cash position increased to $330.9 million at September  26,  1999
from $219.9 million at December 31, 1998.

Worldwide  inventories were $198.6 million at September  26,  1999  compared  to
$228.7  million  at  December 31, 1998.  Inventory levels  as  a  percentage  of
quarterly  sales  were 56% in the third quarter of 1999, down from  74%  in  the
second  quarter of 1999, 88% in the first quarter of 1999, and 72% in the fourth
quarter of 1998.

At  September  26,  1999,  the  Company had $50  million  available  for  future
borrowings  under  an unsecured line of credit agreement at a floating  interest
rate  equal  to  the bank's cost of funds rate plus .625% and an additional  $15
million  under  an unsecured line of credit agreement with a second  bank  at  a
similar interest rate.  No borrowings were outstanding under these facilities at
September  26,  1999.  In connection with the 1998 acquisition  of  Silcon  (see
"Acquisition"  below), the Company acquired $24.8 million in  bank  indebtedness
with interest rates ranging from 4% to 8%.  The Company repaid $12.3 million  of
this  indebtedness during the second half of 1998 and $12.4 million  during  the
first   nine  months  of  1999.   The  Company  had  no  significant   financial
commitments,  other  than those required in the normal course  of  business,  at
September 26, 1999.

Capital  investment  for  the first nine months of 1999 consisted  primarily  of
manufacturing  and office equipment, buildings and improvements,  and  purchased
software  applications.  The nature and level of capital spending were  made  to
improve  manufacturing capabilities, principally in the U.S. and the  Far  East,
and  to  support  the  increased marketing, selling, and administrative  efforts
necessitated  by the Company's growth.  Net capital expenditures  were  financed
from available operating cash.  The Company had no material capital commitments,
other  than  those required in the normal course of business, at  September  26,
1999.

As   part  of  the  Company's  ongoing  efforts  to  capitalize  on  its  global
manufacturing presence, the Company closed its Fort Myers, Florida manufacturing
facility during the third quarter of 1999.  This closure is not expected to have
a  material  adverse  effect on the Company's business,  operating  results,  or
financial condition.

                                10
<PAGE>
The  Company has agreements with the Industrial Development Authority of Ireland
("IDA")  under  which the Company receives grant monies for costs  incurred  for
machinery,  equipment, and building improvements for its  Galway  and  Castlebar
facilities equal to 40% and 60%, respectively, of such costs up to a maximum  of
$13.1 million and $1.3 million, respectively.  Such grant monies are subject  to
the  Company  meeting  certain employment goals and  maintaining  operations  in
Ireland  until  termination of the respective agreements.  The total  cumulative
amounts  of  capital grant claims submitted and received through  September  26,
1999  for the Galway facility were approximately $11.4 million and $8.4 million,
respectively.   The  total cumulative amount of capital grant  claims  submitted
through  September  26, 1999 for the Castlebar facility  was  $1.1  million;  no
capital  grant  claims  had  been received for the  Castlebar  facility.   Under
separate  agreements with the IDA, the Company receives direct reimbursement  of
training  costs  at its Galway and Castlebar facilities for  up  to  $3,000  and
$12,500, respectively, per new employee hired.  The total cumulative amounts  of
training grant claims submitted and received through September 26, 1999 for  the
Galway  facility were approximately $1.2 million and $1.2 million, respectively.
The total cumulative amount of training grant claims submitted through September
26,  1999 for the Castlebar facility was approximately $1.0 million; no training
grant claims had been received for the Castlebar facility.

Management  believes  that current internal cash flows together  with  available
cash,  available credit facilities or, if needed, the proceeds from the sale  of
additional  equity, will be sufficient to support anticipated  capital  spending
and other working capital requirements for the foreseeable future.

Stock Repurchase Program

On  September  10, 1999, the Company announced that the Board of  Directors  had
authorized  the  repurchase  of  up  to ten  million  shares  of  the  Company's
outstanding common stock.  Such purchases of stock may be made through September
10,  2001,  from  time to time on the open market as market conditions  warrant.
The  objective  of  the  repurchase program is to offset potential  dilution  of
earnings per share, which may result from the Company's employee stock ownership
programs.

Shareholder Rights Plan

In September 1999, the Company's Board of Directors adopted a Shareholder Rights
Agreement (the "Plan").  Under the terms of the Plan, which expires in September
2009,  the  Company declared a dividend of one Common Stock Purchase Right  (the
"Rights"),  for  each outstanding share of common stock held  at  the  close  of
business  on  September 13, 1999.  The Rights will become  exercisable,  if  not
earlier  redeemed  or exchanged, only after a person or group has  acquired,  or
announced a tender offer which would result in a person or group acquiring,  15%
or  more  of  the  Company's  common  stock.   In  the  event  a  Right  becomes
exercisable,  the  Plan allows the Company's shareholders  to  purchase,  at  an
exercise  price of $110 per Right, subject to adjustment, common  stock  of  the
Company  having a market value of $220.  The Company will generally be  entitled
to  redeem the Rights at $.01 per Right at any time until a person or group  has
acquired a 15% stock position.  Until exercise, a Right holder, as such, has  no
rights as a shareholder of the Company.

Acquisition of Silcon A/S

Early  in  the  second quarter of 1998, the Company entered  into  a  definitive
agreement with the principal management shareholders of Silcon to acquire  stock
of Silcon, a Denmark-based manufacturer of three-phase UPSs up to 480 kilo volt-
amps  ("kVA"), and the Company commenced a tender offer for Silcon  shares.   In
June  1998,  the  initial  tender offer and purchase  of  stock  from  principal
management shareholders was completed enabling the Company to operate Silcon  as
a  majority-owned  subsidiary.  During the second  half  of  1998,  the  Company
increased  its  ownership  percentage to 89%.   In  January  1999,  the  Company
attained ownership of more than 90% of the share capital of Silcon through  open
market  purchases  financed  from  operating  cash  and  commenced  a  mandatory
redemption  of  the  remaining  Silcon shares.   Through  this  mandatory  share
redemption,  the Company completed its acquisition of the remaining  outstanding
shares  of Silcon in October 1999.  In connection with the mandatory redemption,
the  Copenhagen  Stock  Exchange  approved the  de-listing  of  Silcon's  shares
effective  March  1,  1999.   The Company's cash  outlays  associated  with  the
step-acquisition of $64.4 million during 1998 and $8.3 million during the first
nine months of 1999 were financed from operating cash.

                                11
<PAGE>
The purchase price was allocated to the net tangible and identifiable intangible
assets  acquired and to acquired in-process R&D ("acquired R&D").  Acquired  R&D
includes  the value of products in the development stage that are not considered
to  have  reached technological feasibility and that have no alternative  future
uses.   In accordance with applicable accounting rules, acquired R&D is required
to  be expensed.  Accordingly, $7.6 million of the acquisition cost was expensed
in  1998.   The remaining purchase price exceeded the fair value of the tangible
net  assets  acquired by approximately $53 million, consisting  of  identifiable
intangible  assets  and goodwill, which is being amortized  on  a  straight-line
basis over 15 years.  The acquisition has been accounted for as a purchase  and,
accordingly,  Silcon's  results  of operations are  included  in  the  Company's
consolidated financial statements from the date of acquisition.

Foreign Currency Activity

The  Company  invoices its customers in certain local currencies.  Realized  and
unrealized transaction gains or losses are included in the results of operations
and  are  measured  based upon the effect of changes in exchange  rates  on  the
actual or expected amount of functional currency cash flows.  Transaction  gains
and  losses were not material to the results of operations in the third quarters
and first nine month periods of 1999 and 1998.

At  September  26,  1999  the  Company's significant unhedged  foreign  currency
accounts receivable, by currency, were as follows:
<TABLE>
<CAPTION>
  <S>                         <C>                           <C>
  In thousands                Foreign Currency              US Dollars
  Japanese Yen                       1,371,830                 $13,178
  German Marks                          23,168                  12,386
  European Euros                        11,479                  11,982
  French Francs                         75,056                  11,952
  British Pounds                         5,073                   8,289
  Swiss Francs                           9,310                   6,062
</TABLE>
The  Company  also  had  non-trade  receivables  of  3.9  million  Irish  Pounds
(approximately  US$5.2 million) and short term debt and liabilities  denominated
in  various  European currencies of US$45.8 million, as well as Yen  denominated
liabilities of approximately US$2.8 million.

The  Company  periodically reviews its foreign exchange exposure  and  considers
various  risk  management techniques, including the netting of foreign  currency
receipts  and  disbursements, rate protection agreements with  customers/vendors
and derivatives arrangements, including foreign exchange contracts.  The Company
presently   does   not   utilize  rate  protection  agreements   or   derivative
arrangements.

Recently Issued Accounting Standard

The  Financial Accounting Standards Board recently 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 is effective for all fiscal quarters of fiscal years
beginning after June 15, 2000, as provided for in SFAS No. 137.  The adoption of
this  Statement  is  not  expected to have a material impact  on  the  Company's
consolidated financial position or results of operations.

Year 2000 Readiness Disclosure Statement

Many computer systems were not designed to handle any dates beyond the year 1999
and,  therefore,  many  companies  will be required  to  modify  their  computer
hardware  and  software  prior  to  the year  2000  in  order  to  remain  fully
operational.   During 1998, the Company commenced a year 2000 readiness  program
to  assess  the  impact of the year 2000 issue on the Company's  operations  and
address  necessary remediation.  A year 2000 program director reporting directly
to senior management has been assigned to this project.

                                12
<PAGE>
Assessment of the Company's Products for Year 2000 Compliance
All  of the Company's hardware products and accessories are believed to be  year
2000  compliant,  meaning that they have been tested to verify that  where  date
fields  are processed, dates are calculated and displayed accurately,  and  that
there  are no known defects related to scheduled events such as shutdowns, self-
tests,  and  run-time calibrations and also the handling of unscheduled  events,
such  as  power  failures, which are directly attributable to the millenium  and
century  change,  provided that all other third party products (e.g.,  software,
firmware, operating systems, and hardware) properly exchange date data with  the
Company's  products and provided also that the Company's products  are  used  in
accordance  with  the  product documentation.  The Company  has  also  performed
extensive  testing  of all software products that it is currently  offering  for
licensing  and  has determined that these products are substantially  year  2000
compliant.   Periodically  updated  information  about  the  Company's  software
products  is available at the Company's Year 2000 Readiness Disclosure Web  site
(www.APCC.com).  Information on this site is provided to the Company's customers
for  the sole purpose of assisting in planning for transition to the year  2000.
Such information is the most currently available concerning the behavior of  the
Company's products in the next century and is provided "as is" without  warranty
of any kind.  The Company's year 2000 compliant products recognize the year 2000
as  a leap year.  To the extent the Company's hardware and software products are
combined  with the hardware and software products of other companies, there  can
be  no  assurance that users of the Company's products will not experience  year
2000  problems  as  a  result of the combination of the Company's  hardware  and
software  products with non-compliant products of other companies.  The  Company
currently  does  not anticipate material expenditures to remedy  any  year  2000
issues with respect to its products and services.

Assessment of the Company's Information Technology ("IT") and Non-IT Systems for
Year 2000 Compliance
The  Company's  Oracle  manufacturing  and financial  information  systems  were
implemented during 1998.  The Company has evaluated the year 2000 compliance  of
these  systems  in accordance with Oracle's recommendations.   At  December  31,
1998, the Company had completed its initial installation and testing of software
patches  available  from  Oracle.  During the  second  quarter  of  1999,  final
installation  and  testing of additional software patches completed  efforts  to
bring these systems into compliance.  The Company does not consider the cost  of
the  new  hardware and software for the Oracle implementations to be related  to
year 2000 readiness as these system replacements were already planned to satisfy
the  demands  of expansion of its worldwide operations and were not  accelerated
due  to year 2000 issues.  The Company has conducted an evaluation of its non-IT
systems for compliance, including those related to its manufacturing facilities,
distribution  centers, and production and engineering equipment.   Additionally,
the  Company utilizes other third party software and equipment to distribute its
products  as well as to operate other aspects of its business.  The Company  has
also  conducted  a  review  of  such  software  and  equipment.   The  Company's
evaluation  and  review  of  its non-IT systems and  third  party  software  and
equipment were completed at the end of the third quarter of 1999.  There can  be
no  assurance that such software and equipment is year 2000 compliant, that non-
compliant  software and equipment will be made compliant on a timely  basis,  or
that  any  such non-compliant software and equipment would not have  a  material
adverse effect on the Company's systems and operations.

Evaluation  of Third Parties with which the Company has a Material Relationship,
including Key Suppliers, Service Providers, and Strategic Partners
The  Company's  year  2000  readiness program includes identifying  these  third
parties  and  determining, based on receipt of written verification,  review  of
publicly  available financial statement disclosures, and other means, that  such
third  parties are either in compliance or expect to be in compliance  prior  to
January  1,  2000.   The  Company  has  identified  its  material  third   party
relationships  and  has  communicated  with  its  significant  vendors,  service
providers, and certain strategic partners.  All such efforts, including  written
questionnaires, on-site visitations, and education were completed at the end  of
the  third  quarter of 1999.  Many enterprises, including the Company's  present
and  potential  customers,  may  be devoting  a  substantial  portion  of  their
information systems spending to resolving year 2000 issues, which may result  in
their  spending being diverted from applications such as the Company's products,
over the next year.

Development of Contingency Plans
As  the  Company's  year  2000  readiness program nears  completion,  management
currently believes that its material IT and non-IT systems and equipment will be
compliant  by the year 2000 and that the cost to address year 2000  issues  will
not  be material.  Nevertheless, the Company has identified worst case scenarios

                                13
<PAGE>
involving  the  interruption of critical vendors as a result  of  infrastructure
failures  or third party vendor failures.  The Company completed its contingency
plans  at the end of the third quarter of 1999.  Such plans include but are  not
limited  to  maintaining  appropriate inventory levels,  as  well  as  requiring
critical vendors to maintain certain inventory levels.

It is the Company's policy to expense as incurred all costs associated with year
2000  readiness.  The Company has developed a separate budget for operating  and
capital  expenditures relating to year 2000 issues.  No IT  projects  have  been
deferred  due to year 2000 efforts.  Based on its efforts to date,  the  Company
does not believe that the costs of year 2000 issues will have a material adverse
effect  on  the  Company's business, operating results, or financial  condition.
Although the Company is taking measures to address the impact, if any,  of  year
2000 issues, it cannot predict the outcome or success of its year 2000 readiness
program,  or whether the failure of third party systems or equipment to  operate
properly in the year 2000 will have a material adverse effect upon the Company's
business,  operating results, or financial condition, or require the Company  to
incur unanticipated material expenses to remedy any year 2000 issue.

The  foregoing discussion regarding the Company's year 2000 readiness  program's
implementation,  effectiveness,  and cost, contains  forward-looking  statements
which  are  based  on  management's expectations, determined  utilizing  certain
assumptions  of  future  events,  including third  party  compliance  and  other
factors.   However,  there can be no guarantee that these expectations  will  be
realized,   and  actual  results  could  differ  materially  from   management's
expectations.   Specific  factors  that might cause  such  material  differences
include, but are not limited to, the availability and cost of personnel  trained
in this area and other similar uncertainties, and the remediation success of the
Company's suppliers, service providers, and strategic partners.

Factors That May Affect Future Performance

Statements  contained  in  this  document which are  not  historical  facts  may
constitute  forward-looking  statements  as  that  term  is  defined  under  the
provisions  of  the  "safe harbor" section of the Private Securities  Litigation
Reform  Act  of 1995.  All forward-looking statements are subject to  risks  and
uncertainties  which could cause actual results to differ from those  projected.
The  factors  that could cause actual results to differ materially  include  the
following:   APC's  ability to successfully integrate Silcon's  operations;  the
timely  development  and  acceptance of new products; ramp  up,  expansion,  and
rationalization  of  global manufacturing capacity; general  worldwide  economic
conditions;   growth  rates  in  the  power  protection  industry  and   related
industries,  including  but  not  limited to the  PC,  server,  networking,  and
enterprise  hardware  industries; competitive  factors  and  pricing  pressures;
changes in product mix; changes in the seasonality of demand patterns; inventory
risks  due  to  shifts  in  market demand; the effects  of  any  other  possible
acquisitions;  component  constraints  and  shortages;  risk  of  nonpayment  of
accounts  receivable;  changes in customer order  patterns  and  product  demand
related to year 2000 purchasing issues; impact on the Company's business due  to
internal  systems  or  systems of suppliers and other  third  parties  adversely
affected  by  year  2000  problems; the uncertainty of  the  litigation  process
including  risk  of  an  unexpected, unfavorable result  of  current  or  future
litigation;  and the risks described from time to time in the Company's  filings
with the Securities and Exchange Commission.


ITEM 3.  QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK

The  Company,  in  the  normal course of business, is exposed  to  market  risks
relating  to  fluctuations in foreign currency exchange rates.  The  information
required  under  this section related to such risks is included in  the  Foreign
Currency  Activity section of Management's Discussion and Analysis of  Financial
Condition and Results of Operations in Item 2 of this Report and is incorporated
herein by reference.

                                14
<PAGE>
PART II - OTHER INFORMATION


ITEM 1.  LEGAL PROCEEDINGS

On  or  about  August 20, 1999, General Signal Power Systems,  Inc  (a/k/a  Best
Power)  ("Best")  filed suit against the Company in the United  States  District
Court  for  the  Western District of Wisconsin alleging patent infringement  and
false  advertising.  Best seeks unspecified damages, costs, fees, and injunctive
relief.   The Company intends to vigorously defend against the suit and believes
the  ultimate disposition of this matter will not have a material adverse effect
on  the  Company's consolidated financial position or results of  operations  or
liquidity.  No provision for any liability that may result from this action  has
been recognized in the Company's consolidated financial statements.

On  or about January 27, 1999, the Company was served with a lawsuit filed by an
individual  in  the  United States District Court for the  Central  District  of
California  alleging  patent infringement.  The plaintiff, Anthony  F.  Coppola,
claims  sole  ownership of the patent referenced in the lawsuit.  Coppola  seeks
unspecified damages, costs, fees, and injunctive relief.  On or about April  14,
1999, the Company removed the case from the United States District Court for the
Central  District  of  California to the United States District  Court  for  the
District of Massachusetts.  The Company intends to vigorously defend against the
suit  and  believes  the ultimate disposition of this matter  will  not  have  a
material  adverse  effect on the Company's consolidated  financial  position  or
results  of  operations or liquidity.  No provision for any liability  that  may
result  from  this  action  has been recognized in  the  Company's  consolidated
financial statements.


ITEM 6.  EXHIBITS AND REPORTS ON FORM 8-K

(A)  Exhibits

Exhibit No. 4.01 - Shareholder Rights Agreement, dated as  of  September  2,
          1999,  between the Company and BankBoston, N.A., previously  filed  as
          an  Exhibit to the Company's Current Report on Form 8-K, dated  as  of
          September  3,  1999, which included as Exhibit A the  Form  of  Rights
          Certificate,  and  as  Exhibit B the Summary  of  Rights  to  Purchase
          Common Stock

Exhibit No. 27   - Financial Data Schedule

(B)  Reports on Form 8-K

The  Company filed a Current Report on Form 8-K with the Securities and Exchange
Commission  dated  September 3, 1999, which reported pursuant  to  Item  5,  the
adoption  of  the  Shareholder  Rights  Agreement  by  the  Company's  Board  of
Directors.

                                15
<PAGE>
                                                                       FORM 10-Q
                                                              September 26, 1999


                                   SIGNATURES


      Pursuant  to the requirements 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.


                      AMERICAN POWER CONVERSION CORPORATION

                            Date:  November 10, 1999


                               /s/ Donald M. Muir

                                 Donald M. Muir
                             Chief Financial Officer
                  (Principal Accounting And Financial Officer)

                                16
<PAGE>
                                                                       FORM 10-Q
                                                              September 26, 1999



             AMERICAN POWER CONVERSION CORPORATION AND SUBSIDIARIES
                                  EXHIBIT INDEX
<TABLE>
<CAPTION>
<S>                 <C>                                           <C>
Exhibit Number      Description                                   Page No.

Exhibit No. 4.01*   Shareholder Rights Agreement, dated as of
                    September 2, 1999, between the Company and
                    BankBoston, N.A.

Exhibit No. 27      Financial Data Schedule                          18

*  Previously filed as an Exhibit (Exhibit 4.01) to the Company's Current Report
on Form 8-K, dated as of September 3, 1999, which included as Exhibit A the Form
of Rights Certificate, and as Exhibit B the Summary of Rights to Purchase Common
Stock, and incorporated herein by reference (File No. 1-2432).  The number given
in parenthesis indicates the corresponding exhibit in such Form 8-K.
</TABLE>
                                17