<PAGE>   1

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


                                    FORM 10-Q


                       SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549




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

                  For the quarterly period ended March 31, 2001

Commission File Number 1-12280

                                   BELDEN INC.
             (Exact Name of Registrant as Specified in its Charter)

          DELAWARE                                             76-0412617
(State or Other Jurisdiction of                           (I.R.S. Employer
Incorporation or Organization)                            Identification No.)


                        7701 FORSYTH BOULEVARD, SUITE 800
                            ST. LOUIS, MISSOURI 63105
              (Address of Principal Executive Offices and Zip Code)

                                 (314) 854-8000
              (Registrant's Telephone Number, Including Area Code)


                 Indicate by check mark whether the registrant (1) has filed all
                 reports required to be filed by Section 13 or 15(d) of the
                 Securities Exchange Act of 1934 during the preceding 12 months
                 (or for such shorter period that the registrant was required to
                 file such reports), and (2) has been subject to such filing
                 requirement for the past 90 days.

                 Yes           X          No
                        ----------------        ----------------

                 Number of shares outstanding of the issuer's Common Stock, par
                 value $.01 per share, as of May 8, 2001: 24,545,253 shares

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


Exhibit Index on Page 17                                            Page 1 of 18



<PAGE>   2



                          PART I FINANCIAL INFORMATION

ITEM 1:       FINANCIAL STATEMENTS

CONSOLIDATED BALANCE SHEETS

<TABLE>
<CAPTION>
========================================================================================================================
                                                                                           MARCH 31,        December 31,
                                                                                                2001                2000
------------------------------------------------------------------------------------------------------------------------
(in thousands)                                                                           (UNAUDITED)
<S>                                                                                        <C>                  <C>
ASSETS
Current assets:
    Cash and cash equivalents                                                              $   6,517            $  7,396
    Receivables                                                                              126,384             156,195
    Inventories                                                                              181,331             175,331
    Deferred income taxes                                                                     11,534              12,535
    Other                                                                                     12,748               3,116
                                                                                           ---------            --------
       Total current assets                                                                  338,514             354,573
Property, plant and equipment, less accumulated depreciation                                 344,716             345,060
Goodwill, less accumulated amortization                                                       76,453              80,552
Intangibles, less accumulated amortization                                                     9,052               9,636
Other assets                                                                                   5,577               5,947
                                                                                           ---------            --------
                                                                                           $ 774,312            $795,768
                                                                                           =========            ========
LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities:
    Accounts payable and accrued liabilities                                               $ 110,292            $142,871
    Income taxes payable                                                                       5,400               4,352
                                                                                           ---------            --------
       Total current liabilities                                                             115,692             147,223
Long-term debt                                                                               274,656             272,630
Postretirement benefits other than pensions                                                   12,414              12,242
Deferred income taxes                                                                         63,101              61,049
Other long-term liabilities                                                                   13,676              14,955
Stockholders' equity:
    Preferred stock                                                                                -                   -
    Common stock                                                                                 262                 262
    Additional paid-in capital                                                                46,352              47,379
    Retained earnings                                                                        307,610             297,625
    Accumulated other comprehensive loss                                                     (25,681)            (21,933)
    Unearned deferred compensation                                                            (1,668)                  -
    Treasury stock                                                                           (32,102)            (35,664)
                                                                                           ---------            --------
       Total stockholders' equity                                                            294,773             287,669
                                                                                           ---------            --------
                                                                                           $ 774,312            $795,768
========================================================================================================================
</TABLE>

See accompanying notes.

                                      -2-


<PAGE>   3



CONSOLIDATED INCOME STATEMENTS
(UNAUDITED)

<TABLE>
<CAPTION>
=======================================================================================================================
Three Months Ended March 31,                                                                  2001                 2000
-----------------------------------------------------------------------------------------------------------------------

(in thousands, except per share data)
<S>                                                                                      <C>                  <C>
Revenues                                                                                 $ 251,828            $ 228,009
Cost of sales                                                                              202,519              181,139
                                                                                         ---------            ---------
    Gross profit                                                                            49,309               46,870
Selling, general and administrative expenses                                                27,715               27,001
Amortization of goodwill                                                                       508                  495
                                                                                         ---------            ---------
    Operating earnings                                                                      21,086               19,374
Other income, net                                                                           (1,200)                   -
Interest expense                                                                             4,780                4,518
                                                                                         ---------            ---------
    Income before taxes                                                                     17,506               14,856
Income taxes                                                                                 6,040                5,497
                                                                                         ---------            ---------
    Income before cumulative effect of change in accounting principle                       11,466                9,359
Cumulative effect of change in accounting principle, net of tax benefit
    of $133                                                                                   (251)                   -
                                                                                         ---------            ---------
       Net income                                                                        $  11,215            $   9,359
                                                                                         =========            =========
Basic earnings per share                                                                 $     .46            $     .38
Diluted earnings per share                                                               $     .45            $     .38
                                                                                         =========            =========
Dividends declared per share                                                             $     .05            $     .05
=======================================================================================================================
</TABLE>

See accompanying notes.

                                      -3-

<PAGE>   4


CONSOLIDATED CASH FLOW STATEMENTS
(UNAUDITED)

<TABLE>
<CAPTION>
========================================================================================================================
Three Months Ended March 31,                                                                     2001               2000
------------------------------------------------------------------------------------------------------------------------
(in thousands)
<S>                                                                                         <C>                 <C>
Cash flows from operating activities:
    Net income                                                                              $  11,215           $  9,359
    Adjustments to reconcile net income to net cash provided by operating
       activities:
       Depreciation                                                                             8,076              7,207
       Amortization                                                                             1,506              1,579
       Deferred income taxes                                                                     (582)             3,023
       Cumulative effect of change in accounting principle                                        251                  -
       Gain on business divestiture                                                            (1,200)                 -
       Other, net                                                                                  73                  -
       Changes in operating assets and liabilities(*):
          Receivables                                                                          27,080             13,633
          Inventories                                                                          (8,703)           (13,299)
          Accounts payable and accrued liabilities                                            (30,362)           (20,273)
          Income taxes payable                                                                  4,896              2,702
          Other assets and liabilities, net                                                   (11,739)             3,412
                                                                                            ---------           --------
              Net cash provided by operating activities                                           511              7,343
Cash flows from investing activities:
    Capital expenditures                                                                       (7,429)            (7,022)
    Proceeds from business divestiture                                                          1,400                  -
                                                                                            ---------           --------
              Net cash used for investing activities                                           (6,029)            (7,022)
Cash flows from financing activities:
    Net borrowings/(payments) under long-term credit facility and credit
          agreements                                                                            5,298             (1,842)
    Proceeds from the exercise of stock options                                                   795                202
    Cash dividends paid                                                                        (1,221)            (1,210)
                                                                                            ---------           --------
              Net cash provided by/(used for) financing activities                              4,872             (2,850)
Effect of exchange rate changes on cash and cash equivalents                                     (233)               (21)
                                                                                            ---------           --------
Decrease in cash and cash equivalents                                                            (879)            (2,550)
Cash and cash equivalents, beginning of period                                                  7,396              3,874
                                                                                            ---------           --------
Cash and cash equivalents, end of period                                                    $   6,517           $  1,324
                                                                                            =========           ========
Supplemental cash flow information:
    Income taxes paid, net of refunds                                                       $   1,249           $    561
    Interest paid, net of amount capitalized                                                    8,457              8,345
========================================================================================================================
</TABLE>


See accompanying notes.

(*) Net of the effects of exchange rate changes and acquired businesses.


                                      -4-

<PAGE>   5


STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY
FOR THE THREE MONTH PERIODS ENDED MARCH 31, 2001 AND 2000
(UNAUDITED)

<TABLE>
<CAPTION>
=================================================================================================================================
                                                                                                           Accumulated
                                   Common Stock                          Treasury Stock       Unearned        Other
                                  --------------  Paid-In   Retained   -----------------      Deferred    Comprehensive
                                  Shares  Amount  Capital   Earnings   Shares    Amount     Compensation       Loss        Total
--------------------------------------------------------------------------------------------------------------------------------
(in thousands)
<S>                               <C>      <C>    <C>       <C>        <C>      <C>            <C>            <C>        <C>
Balance at December 31, 1999      26,204   $262   $47,958   $249,653   (1,826)  ($37,296)      $     -        ($13,050)  $247,527

Net income                                                     9,359                                                        9,359

Foreign currency translation
    adjustments                                                                                                 (4,841)    (4,841)
                                                                                                                         --------

    Comprehensive income                                                                                                    4,518

Issuance of common stock for:
    Stock options                                    (202)                 26        490                                      288

Cash dividends
    ($.05 per share)                                          (1,210)                                                      (1,210)

                                  ------   ----   -------   --------   ------   --------       -------        --------   --------
Balance at March 31, 2000         26,204   $262   $47,756   $257,802   (1,800)  ($36,806)      $     -        ($17,891)  $251,123
                                  ======   ====   =======   ========   ======   ========       =======        ========   ========

Balance at December 31, 2000      26,204   $262   $47,379   $297,625   (1,774)  ($35,664)      $     -        ($21,933)  $287,669

Net income                                                    11,215                                                       11,215

Foreign currency translation
    adjustments                                                                                                 (3,469)    (3,469)

Unrealized loss on derivative
    instruments                                                                                                   (279)      (279)
                                                                                                                         --------

    Comprehensive income                                                                                                    7,467

Issuance of common stock for:
    Stock options                                    (682)                 47      1,476                                      794
    Stock compensation                               (345)                 66      2,086        (1,741)                         -

Amortization of unearned
    deferred compensation                                                                           73                         73

Cash dividends
    ($.05 per share)                                          (1,230)                                                      (1,230)

                                  ------   ----   -------   --------   ------   --------       -------        --------   --------
Balance at March 31, 2001         26,204   $262   $46,352   $307,610   (1,661)  ($32,102)      ($1,668)       ($25,681)  $294,773
=================================================================================================================================
</TABLE>

See accompanying notes.

                                      -5-


<PAGE>   6


NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
(UNAUDITED)

NOTE 1: SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Basis of Presentation
The accompanying Consolidated Financial Statements include Belden and all of its
subsidiaries. All significant intercompany accounts and transactions are
eliminated in consolidation. The financial information presented as of any date
other than December 31, 2000 and December 31, 1999 has been prepared from the
books and records without audit. The accompanying Consolidated Financial
Statements have been prepared in accordance with the instructions to Form 10-Q
and do not include all of the information and the footnotes required by
accounting principles generally accepted in the United States for complete
statements. In the opinion of management, all adjustments, consisting only of
normal recurring adjustments, necessary for a fair presentation of such
financial statements have been included. These Consolidated Financial Statements
should be read in conjunction with the Consolidated Financial Statements and
notes thereto contained in the Company's Annual Report on Form 10-K for the year
ended December 31, 2000.

NOTE 2:  INVENTORIES

<TABLE>
<CAPTION>
===========================================================================================
                                                              MARCH 31,        December 31,
                                                                  2001                2000
-------------------------------------------------------------------------------------------
(in thousands)
<S>                                                           <C>                 <C>
Raw materials                                                 $  44,356           $  46,671
Work-in-process                                                   8,207               7,883
Finished goods                                                  141,606             134,570
Perishable tooling and supplies                                   7,516               7,312
                                                              ---------           ---------
                                                                201,685             196,436
Excess of current standard costs over LIFO costs                (12,220)            (13,129)
Obsolescence and other reserves                                  (8,134)             (7,976)
                                                              ---------           ---------
    Net inventories                                           $ 181,331           $ 175,331
===========================================================================================
</TABLE>

NOTE 3:  PER SHARE INFORMATION

The following table sets forth the computation of basic and diluted earnings per
share:

<TABLE>
<CAPTION>
===================================================================================
Three Months Ended March 31,                                    2001           2000
-----------------------------------------------------------------------------------
(in thousands, except per share data)
<S>                                                          <C>            <C>
Numerator:
  Net Income                                                 $11,215        $ 9,359
                                                             =======        =======
Denominator:
  Denominator for basic earnings per share - weighted
       average shares                                         24,471         24,384
Effect of dilutive employee stock options                        344            172
                                                             -------        -------
  Denominator for dilutive earnings per share - adjusted
       weighted average shares                                24,815         24,556
                                                             -------        -------
Basic earnings per share                                     $   .46        $   .38
Diluted earnings per share                                   $   .45        $   .38
===================================================================================
</TABLE>


                                      -6-

<PAGE>   7


NOTE 4: BUSINESS SEGMENT AND GEOGRAPHIC INFORMATION

The Company conducts its operations through two business segments--the
Electronics segment and the Communications segment. The Electronics segment
designs, manufactures and markets metallic and fiber optic wire and cable
products with communications, entertainment, industrial and networking
applications. These products are sold primarily through distributors. The
Communications segment designs, manufactures, and markets metallic cable
products primarily with communications and networking applications. These
products are sold to Local Exchange Carriers ("LECs") either directly or through
contractors designated by the LECs.

The Company evaluates performance and allocates resources based on operating
earnings before interest and income taxes.

Operating earnings of the two principal businesses include all the ongoing costs
of operations. Allocations to or from these businesses are immaterial. With the
exception of certain unallocated tax assets, substantially all the business
assets are the owned assets of each of the business segments. Segment
information below the quantitative threshold is attributable to corporate
headquarters.

BUSINESS SEGMENT INFORMATION

<TABLE>
<CAPTION>
=========================================================================================================================
                                                                                            CORPORATE &
THREE MONTHS ENDED MARCH 31, 2001                       ELECTRONICS      COMMUNICATIONS     ELIMINATIONS     CONSOLIDATED
-------------------------------------------------------------------------------------------------------------------------
(IN THOUSANDS)
<S>                                                       <C>                <C>              <C>             <C>
REVENUES                                                  $ 163,843          $87,985          $    -          $ 251,828
INTERSEGMENT REVENUES                                         2,267            4,608          (6,875)                 -
OPERATING EARNINGS                                           18,624            5,109          (2,647)            21,086
OTHER INCOME, NET                                            (1,200)               -               -             (1,200)
INTEREST EXPENSE                                                  -                -           4,780              4,780
INCOME BEFORE TAXES                                          19,824            5,109          (7,427)            17,506
=========================================================================================================================
<CAPTION>
=========================================================================================================================
                                                                                            Corporate &
Three Months Ended March 31, 2000                       Electronics      Communications     Eliminations     Consolidated
-------------------------------------------------------------------------------------------------------------------------
(in thousands)
<S>                                                    <C>              <C>               <C>            <C>
Revenues                                                   $175,860          $52,149          $    -          $ 228,009
Intersegment revenues                                           800            7,172          (7,972)                 -
Operating earnings                                           18,030            1,695            (351)            19,374
Other income, net                                                 -                -               -                  -
Interest expense                                                  -                -           4,518              4,518
Income before taxes                                          18,030            1,695          (4,869)            14,856
=========================================================================================================================
<CAPTION>

GEOGRAPHIC INFORMATION

=========================================================================================================================
Three Months Ended March 31,                                             2001                        2000
                                                                           PERCENT OF                    Percent of
(in thousands, except % data)                                   REVENUES      REVENUE         Revenues      Revenue
-------------------------------------------------------------------------------------------------------------------------
<S>                                                             <C>              <C>          <C>              <C>
US & Canada                                                     $179,526          71%         $169,517          74%
Europe                                                            54,273          22%           38,420          17%
Asia/Pacific                                                      10,761           4%           11,581           5%
Latin America                                                      5,288           2%            6,818           3%
Other                                                              1,980           1%            1,673           1%
                                                                --------         ---          --------         ---
Total                                                           $251,828         100%         $228,009         100%
=========================================================================================================================
</TABLE>


                                      -7-

<PAGE>   8


NOTE 5: BUSINESS DIVESTITURE

In February 2001, the Company completed the sale of its 70% ownership interest
in MCTEC B.V. of Venlo, Netherlands ("MCTEC") to STS Biopolymers Inc. ("STS").
The Company received cash proceeds of approximately $1.4 million and recorded a
gain as a result of the transaction of approximately $1.2 million before tax or
$767 thousand ($.03 per share--diluted) after tax. The Company will also receive
additional payments from STS over the next 7 years for the sale of technology
rights associated with the products manufactured by MCTEC. Operating earnings
for MCTEC were $295 thousand and $195 thousand for 2000 and 1999, respectively.

NOTE 6: FINANCIAL RISK MANAGEMENT

On January 1, 2001, the Company adopted Statement of Financial Accounting
Standards ("SFAS") No. 133, Accounting for Derivative Instruments and Hedging
Activities, as amended by SFAS No. 137 and SFAS No. 138. In accordance with the
provisions of SFAS No. 133, the Company recorded a negative transition
adjustment upon adoption of the standard to recognize its outstanding derivative
instruments at fair value. This transition adjustment represented an
approximately $251 thousand ($384 thousand pre-tax) or $0.01 per share--diluted
loss that was reflected on the Consolidated Income Statements as the cumulative
effect of changes in accounting principle. The Company also recorded a negative
transition adjustment of approximately $317 thousand ($484 thousand pre-tax) in
Accumulated Other Comprehensive Loss to recognize a previously deferred loss on
a settled interest rate forward derivative. The portion of the transition
adjustment recorded in Accumulated Other Comprehensive Loss as of January 1,
2001 that the Company will reclassify into earnings during the next twelve
months is not material to its financial statements.

The Company is exposed to various market risks such as changes in interest
rates, currency exchange rates and commodity pricing. To manage the volatility
relating to exposures, the Company nets the exposures on a consolidated basis to
take advantage of natural offsets. For residual exposures, the Company enters
into various derivative transactions pursuant to the Company's policies in areas
such as counterparty exposure and hedging practices. The terms of such
instruments and the transactions to which they relate generally do not exceed 12
months. The Company does not hold or issue derivative instruments for trading
purposes

Raw materials used by the Company, primarily copper, are subject to price
volatility caused by supply conditions, political and economic variables and
other unpredictable factors. As part of its risk management strategy, the
Company uses exchange-traded forward contracts to manage its exposure to changes
in copper costs. Each contract obligates the Company to make or receive a
payment equal to the net change in the value of the contract at its maturity.
Due to the Company's limited derivative activity, the relatively short tenors of
the derivative instruments and the anticipated immaterial impact of derivative
valuation gains and losses on financial results, the Company has elected to
treat these instruments as derivatives not designated as hedges. Gains and
losses resulting from changes in the fair value of these instruments are
recognized in operating income on a quarterly basis.

The fair value of these derivatives at March 31, 2001 was approximately $9.4
million. For the three months ended March 31, 2001, the Company recognized an
approximate $247 thousand net loss resulting from changes in the fair value of
these derivatives.


                                      -8-

<PAGE>   9


NOTE 7:  RESTRICTED STOCK AWARDS

On February 14, 2001, the Company issued 66,000 restricted stock awards to a
number of its key employees. Participants will receive a stated amount of the
Company's common stock provided they remain employed with the Company for three
years from the grant date. This award has been accounted for under Accounting
Principles Board Opinion No. 25, Accounting for Stock Issued to Employees, as a
fixed plan since both the aggregate number of awards issued and the aggregate
amount to be paid by the participants for the common stock is known.
Compensation related to the awards is measured as the difference between the
market price of the Company's common stock at the grant date and the amount to
be paid by the participants for the common stock. At the grant date, the Company
recognized unearned deferred compensation of $1.7 million. Unearned deferred
compensation is amortized to earnings over the three-year vesting period. For
the quarter ended March 31, 2001, the Company recognized $72.5 thousand in
compensation expense related to the restricted stock awards.

NOTE 8:  INCOME TAXES

For years beginning after December 31, 2000, the Company no longer records
residual United States income tax on undistributed earnings generated by certain
foreign subsidiaries since the Company does not anticipate the remittance of
such earnings to the United States within the foreseeable future. The Company
did not record potential residual United States income taxes of $0.3 million, or
$0.01 per share--diluted, on $3.5 million undistributed foreign earnings for the
three months ended March 31, 2001

The difference between the effective rate reflected in the provision for income
taxes on income before taxes and the amounts determined by applying the
applicable statutory United States tax rate for the three months ended March 31,
2001 are analyzed below:

<TABLE>
<CAPTION>
=====================================================================
THREE MONTHS ENDED MARCH 31, 2001                  AMOUNT      RATE
---------------------------------------------------------------------
(IN THOUSANDS, EXCEPT RATE DATA)
<S>                                                <C>        <C>
PROVISION AT STATUTORY RATE                        $6,127     35.00 %
STATE INCOME TAXES                                    406      2.32 %
LOWER FOREIGN TAX RATES AND OTHER                    (494)    (2.82)%
                                                   ------     -----
TOTAL TAX                                          $6,039     34.50 %
=====================================================================
</TABLE>


NOTE 9:  LONG-TERM DEBT AND OTHER BORROWING ARRANGEMENTS

At March 31, 2001, short-term borrowings in the amount of $75 million were
reclassified to long-term debt, reflecting the Company's intention and ability
to refinance the amounts during the next year on a long-term basis. In this
regard, the Company has received commitments from certain lenders that would
allow the Company to do so.


                                      -9-


<PAGE>   10



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

The following discussion and analysis, as well as the accompanying Consolidated
Financial Statements and related footnotes, will aid in the understanding of the
Company's results of operations as well as its financial position, cash flows,
indebtedness and other key financial information. The following discussion may
contain forward-looking statements. In connection therewith, please see the
cautionary statements contained herein, which identify important factors that
could cause actual results to differ materially from those in the
forward-looking statements.

CONSOLIDATED OPERATING RESULTS
The following table sets forth information comparing consolidated operating
results for the three months ended March 31, 2001 with the three months ended
March 31, 2000.

<TABLE>
<CAPTION>
===========================================================================
Three Months Ended March 31,                            2001           2000
---------------------------------------------------------------------------
(In thousands)
<S>                                                <C>            <C>
Revenues                                           $ 251,828      $ 228,009
Gross profit                                          49,309         46,870
Operating earnings                                    21,086         19,374
Other income, net                                     (1,200)             -
Interest expense                                       4,780          4,518
Income before taxes                                   17,506         14,856
Income before cumulative effect of change in
    accounting principle                              11,466          9,359
Cumulative effect of change in accounting
    principle, net of tax benefit                       (251)             -
Net income                                            11,215          9,359
===========================================================================
</TABLE>

BUSINESS SEGMENTS
The Company conducts its operations through two business segments--the
Electronics segment and the Communications segment. The Electronics segment
designs, manufactures and markets metallic and fiber optic wire and cable
products with communications, entertainment, industrial, and networking
applications. These products are sold chiefly through distribution. The
Communications segment designs, manufactures, and markets metallic cable
products primarily with communications and networking applications. These
products are sold to Local Exchange Carriers ("LECs") either directly or through
contractors designated by the LECs.

The following table sets forth information comparing the Electronics segment
operating results for the three months ended March 31, 2001 with the three
months ended March 31, 2000.

<TABLE>
<CAPTION>
===========================================================================
Three Months Ended March 31,                       2001                2000
---------------------------------------------------------------------------
(In thousands)
<S>                                            <C>                <C>
Revenues                                       $166,110           $ 176,660
Operating earnings                               18,624              18,030
  As a percent of revenues                         11.2%               10.2%
===========================================================================
</TABLE>


                                      -10-


<PAGE>   11



The following table sets forth information comparing the Communications segment
operating results for the three months ended March 31, 2001 with the three
months ended March 31, 2000.


<TABLE>
<CAPTION>
=================================================================
Three Months Ended March 31,                2001             2000
-----------------------------------------------------------------
(In thousands)
<S>                                     <C>              <C>
Revenues                                $ 92,593         $ 59,321
Operating earnings                         5,109            1,695
  As a percent of revenues                   5.5%             2.9%
=================================================================
</TABLE>

ACQUISITIONS
On April 3, 2000, Belden purchased certain assets and assumed certain
liabilities of the metallic communications cable operations of Corning
Communications Limited in Manchester, United Kingdom ("Manchester"). Manchester
designs, manufactures and markets metallic cable products primarily for the
British communications market. This acquisition was accounted for under the
purchase method of accounting. Operating results for Manchester have been
included in the results of operations for the Communications segment since the
acquisition date and may affect comparability of the results of operations
between years.


RESULTS OF OPERATIONS--
THREE MONTHS ENDED MARCH 31, 2001 COMPARED WITH THREE MONTHS ENDED
MARCH 31, 2000

REVENUES
Revenues increased 10.4% to $251.8 million in the three months ended March 31,
2001 from $228.0 million in the three months ended March 31, 2000. Revenue
growth came from a variety of sources.

The acquisition of Manchester in the second quarter of 2000 contributed
approximately 7.9% of the period-over-period revenue growth.

Modest increases in net unit sales contributed approximately 2.4% of the
period-over-period revenue growth. Strong volume gains were achieved on plastic
insulated cable, service distribution wire and high-performance communications
products. Partially offsetting the volume gains achieved on products with
communications applications were decreases in unit sales of products with
networking, industrial and entertainment/OEM applications.

The Company increased unit sales of its plastic insulated cable and service
distribution wire products through market penetration. This increase stemmed
from incremental contract business awarded by a LEC in the U.S. during the
second quarter of 2000. There was also increased demand for high-performance
communications products such as mini-coaxial cable and single-mode fiber optic
cable primarily in the Americas.

Revenues generated for the three months ended March 31, 2001 on products with
networking applications were down compared to the same period of 2000. This
decrease stemmed from the slowing American economy, the absence from this market
in first quarter 2001 of a significant North American distributor that sought
insolvency protection in fourth quarter 2000 and both lower project activity and
increased competition from export and local suppliers in the Asia/Pacific
markets.

                                      -11-

<PAGE>   12

Decreased demand for the Company's specialty electronics products with
industrial applications resulted in a revenue decline compared to the same
period of 2000. This negative period-over-period performance resulted from the
slowing American and Canadian economies, the absence of the failed North
American distributor from this market in first quarter 2001, limited computer
interconnect project activity in the Asia/Pacific markets and the planned exit
of the medical wire business in mid-February 2001.

Revenues generated for the three months ended March 31, 2001 on products with
entertainment/OEM applications were down compared to the same period of 2000.
This negative period-over-period performance resulted from the slowing American
economy, non-recurring project business (the Sydney Olympics) in the Australian
market and the planned exit of the molded cable assemblies business in second
quarter 2000.

The Company experienced some strengthening in price on its broadband, specialty
electronics, broadcast and entertainment products. Approximately 1.8% of the
period-over-period increase in revenues resulted from the current period impact
of pricing actions taken on these products throughout 2000 and the impact of
higher average copper prices. These increases were partially offset by lower
prices for plastic insulated cable and service distribution wire products.

Offsetting the positive impact that acquisitions, volume and pricing had on
period-over-period revenue comparisons was unfavorable foreign currency
translation on European and Asia/Pacific revenues. The decline of the euro,
British pound and Australian dollar from average exchange values of $0.99, $1.61
and $0.63, respectively, in first quarter 2000 to $0.93, $1.46 and $0.53,
respectively, in first quarter 2001 accounted for an approximate 1.7% decline in
period-over-period revenues.

COSTS, EXPENSES AND EARNINGS
The following table sets forth information comparing the components of earnings
for the three months ended March 31, 2001 with the three months ended March 31,
2000.

<TABLE>
<CAPTION>
==================================================================================
                                                                        % Increase
                                                                     2001 Compared
Three Months Ended March 31,              2001           2000            With 2000
----------------------------------------------------------------------------------
(in thousands, except % data)
<S>                                     <C>            <C>                   <C>
Gross profit                            $49,309        $46,870                5.2%
  As a percent of revenues                 19.6%          20.6%
Operating earnings                      $21,086        $19,374                8.8%
  As a percent of revenues                  8.4%           8.5%
Income before taxes                     $17,506        $14,856               17.8%
  As a percent of revenues                  7.0%           6.5%
Net income                              $11,215        $ 9,359               19.8%
  As a percent of revenues                  4.5%           4.1%
=================================================================================
</TABLE>

Gross profit increased 5.2% to $49.3 million in the three months ended March 31,
2001 from $46.9 million in the three months ended March 31, 2000 due primarily
to higher revenues and secondarily to improved profitability within both
business segments. This improvement represents the current quarter impact of
positive pricing actions taken on certain broadband, specialty electronics,
broadcast and entertainment product lines during 2000, the impact of material
cost reductions in the Americas, the impact of lower overhead costs associated
with prior-year plant consolidations and a continuing mix shift toward
higher-bandwidth, higher-margin products. Gross profit as a percent of revenues
declined

                                      -12-

<PAGE>   13


by 1.0 percentage point from the prior year as the Company's currently
lower-margin Communications segment represented a much larger share of total
operations in first quarter 2001 than it did in first quarter 2000.

Operating earnings increased 8.8% to $21.1 million in the three months ended
March 31, 2001 from $19.4 million in the three months ended March 31, 2000 due
primarily to higher gross profit. Also contributing to this increase was an
improvement in selling, general and administrative expenses to 11.2% of revenues
in first quarter 2001 from 12.1% of revenues in first quarter 2000. This
improvement reflects tighter spending controls throughout the organization.
Operating earnings as a percent of revenues declined by 0.1 percentage points
from the prior year due to the impact of the Company's currently lower-margin
Communications segment.

Income before taxes increased 17.8% to $17.5 million in the three months ended
March 31, 2001 from $14.9 million in the three months ended March 31, 2000 due
chiefly to higher operating earnings and the gain recognized on the Company's
sale of its ownership interest in a medical wire joint venture. The higher
operating earnings were partially offset by increased interest expense. Interest
expense increased 5.8% to $4.8 million in first quarter 2001 from $4.5 million
in first quarter 2000 despite lower average borrowings due to marginally higher
interest rates. Average debt outstanding during the first three months of 2001
and 2000 was $277 million and $290 million, respectively. The Company's average
interest rate was 7.1% in the first quarter of 2001 compared to 6.5% in the
first quarter of 2000.

The Company's effective tax rate was 34.5% and 37.0% for the three months ended
March 31, 2001 and 2000, respectively. The period-over-period decrease stemmed
primarily from the Company's assessment under Accounting Principles Board
Opinion No. 23, Accounting for Income Taxes--Special Areas, that undistributed
earnings from its European and Australian subsidiaries would not be remitted to
the United States in the foreseeable future.

Net income increased 19.8% to $11.2 million in the three months ended March 31,
2001 from $9.4 million in the three months ended March 31, 2000 due mainly to
higher income before taxes and the lower effective tax rate partially offset by
the cumulative effect of the Company's adoption of Statement of Financial
Accounting Standards No. 133, Accounting for Derivative Instruments and Hedging
Activity, on January 1, 2001.

ELECTRONICS SEGMENT
Revenues decreased 6.0% to $166.1 million for the quarter ended March 31, 2001
from $176.7 million for the quarter ended March 31, 2000. This decrease can be
attributed mainly to weakening demand for the Company's broadband, networking,
industrial and entertainment/OEM products in the slowing North American markets
as well as the negative effect of currency translation on European and
Asia/Pacific revenues. This decrease was partially offset by the current-quarter
impact of positive pricing actions taken during 2000 on certain broadband,
industrial, broadcast and entertainment products and strong demand for the
segment's fiber optic cable and mini-coaxial cable products.

A North American distributor that purchased product from the Company sought
insolvency protection late in the year. The Company is actively engaged in
offsetting the impact the insolvency may have on its 2001 sales. There can be no
assurance that the Company will be able to replace entirely the planned sales to
be made to the distributor in 2001, but the Company is using its best efforts to
do so through its extensive distributor network.


                                      -13-

<PAGE>   14

Operating earnings increased 3.3% to $18.6 million for the quarter ended March
31, 2001 from $18.0 million for the quarter ended March 31, 2000. As a percent
of revenues, they increased to 11.2% from 10.2%. These results reflected the
current-quarter impact of positive pricing actions taken in 2000 and a favorable
leveraging of both production period costs and selling, general and
administrative expenses.

COMMUNICATIONS SEGMENT
The Communications segment recorded revenues of $92.6 million for the quarter
ended March 31, 2001, a 56.1% increase from revenues of $59.3 million for the
quarter ended March 31, 2000. Nearly half of this strong increase is attributed
to market penetration resulting from a recent LEC contract award, while the
remainder came from the Manchester acquisition.

Operating earnings increased 201.4% to $5.1 million for the quarter ended March
31, 2001 from $1.7 million for the quarter ended March 31, 2000. Operating
earnings as a percent of revenues increased to 5.5% in the quarter ended March
31, 2001 from 2.9% in the same period of 2000. These results reflected the
positive impact of material cost reduction initiatives as well as the successful
leveraging of fixed costs over a much higher revenue base.

FINANCIAL CONDITION

LIQUIDITY AND CAPITAL RESOURCES
The Company has a $200 million Credit Agreement with a group of 7 banks. The
Credit Agreement is unsecured and expires in November 2001. At March 31, 2001,
the Company had no borrowings outstanding under the Credit Agreement. In
addition, as of March 31, 2001, the Company had unsecured, uncommitted
arrangements with 8 banks under which it may borrow up to $102 million at
prevailing interest rates. At March 31, 2001, the Company had $75 million
outstanding under these arrangements.

The Company also had privately-placed debt of $200 million outstanding at March
31, 2001. Details regarding maturities and interests rates are shown below.

<TABLE>
<CAPTION>
=========================================================================================
Note Series                          Principal Balance   Maturity Date      Interest Rate
-----------------------------------------------------------------------------------------
<S>                                     <C>               <C>                  <C>
Senior Notes, Series 1997-A             $75,000,000       08/11/2009*          6.92%
Senior Notes, Series 1999-A              64,000,000       09/01/2004           7.60%
Senior Notes, Series 1999-B              44,000,000       09/01/2006           7.74%
Senior Notes, Series 1999-C              17,000,000       09/01/2009           7.95%
========================================================================================
</TABLE>

*  The Senior Notes, Series 1997-A include an amortizing maturity feature. The
   Company is required to repay $15 million in principal per annum beginning
   August 11, 2005.

The Note Purchase Agreements for these private placements contain affirmative
and negative covenants including a minimum net worth and a maximum ratio of debt
to total capitalization.

The Company expects that cash provided by operations and borrowings available
under its credit agreements will provide it with sufficient liquidity to meet
its operating needs, fund its normal dividends and fund anticipated capital
expenditures.


                                      -14-

<PAGE>   15



During the three months ended March 31, 2001, the Company increased debt by $2
million as cash required to fund working capital investment exceeded cash
provided by operations and certain other investing and financing activities.
However, the Company's debt-to-total-capitalization ratio decreased from 48.7%
at December 31, 2000 to 48.2% at March 31, 2001.

At March 31, 2001, short-term borrowings were reclassified to long-term debt,
reflecting the Company's intention and ability to refinance the amounts during
the next year on a long-term basis. In this regard, the Company has received
commitments from certain lenders that would allow the Company to do so.

WORKING CAPITAL
For the first three months in 2001, operating working capital (defined as
current assets less current liabilities) increased $15 million. This increase
primarily resulted from a higher inventory level in the Communications segment
of the Company. This higher inventory level resulted from a stock buildup in the
U.S. due to (a) lower-than-anticipated unit sales throughout the quarter and (b)
the need to adequately service an expanded LEC contract awarded to the
Communications segment early in the year.

CAPITAL EXPENDITURES
For the first three months in 2001, the Company had capital expenditures of $7.4
million, primarily for modernization and enhancement of machinery and equipment.
The Company plans on spending approximately $45 million during 2001 on these and
similar projects.

OUTLOOK

The level of earnings the Company expected to achieve in 2001 was based on an
assumption that the United States economy would continue to enjoy moderate
growth. This now appears to be in doubt. During the first quarter of 2001,
Belden initiated several contingency plans related to reductions in expected
demand. Based on the impact of a slower economy, particularly in North America,
management believes that the Company's annual revenues will not reach or exceed
last year's level. Revenues are expected to be lower reflecting reduced market
demand in the North American operations of the Electronics segment and in the
Company's European communications business. In response to these general market
conditions, the Company is reducing costs and has adjusted price levels based on
competitive conditions.

FORWARD-LOOKING STATEMENTS

The statements set forth in this Quarterly Report on Form 10-Q other than
historical facts are forward-looking statements made in reliance upon the safe
harbor of the Private Securities Litigation Reform Act of 1995. As such, they
are based on current expectations, estimates, forecasts and projections about
the industries in which the Company operates, general economic conditions and
management's beliefs and assumptions. These statements are not guarantees of
future performance and involve certain risks, uncertainties and assumptions,
which are difficult to predict. As a result, the Company's actual results may
differ materially from what is expected or forecasted in such forward-looking
statements. The Company undertakes no obligation to update any forward-looking
statements, whether as a result of new information, future events or otherwise,
and disclaims any obligation to do so.

The Company's actual results may differ materially from such forward-looking
statements for the following reasons: the unsettled economic conditions of the
Asia/Pacific region (and the impact such conditions may have on the Company's
sales); increasing price, product and service competition from U.S.


                                      -15-


<PAGE>   16


and non-U.S. competitors (including new entrants); the credit worthiness of the
Company's customers; the Company's ability to continue to introduce, manufacture
and deploy competitive new products and services on a timely, cost-effective
basis; the achievement of lower costs and expenses; the ability to successfully
integrate the operations and businesses of acquired companies (including the
Company's achieving cost-saving and profit improvement initiatives at its
Communications operations); the ability to transfer production to new
facilities; developments in technology; the threat of displacement from
competing technologies (including wireless and fiber optic technologies); demand
and acceptance of the Company's products by customers and end users; changes in
raw material costs and availability; changes in foreign currency exchange rates;
the pricing of the Company's products; the success of implementing cost-saving
programs and initiatives; reliance on large customers; general industry and
market conditions and growth rates; and other factors noted elsewhere in the
Company's 2000 Annual Report on Form 10-K and other Securities and Exchange Act
filings.


                                      -16-


<PAGE>   17


                            PART II OTHER INFORMATION


ITEM 6:    EXHIBITS AND REPORTS ON FORM 10-Q

       None.



                                      -17-


<PAGE>   18


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.


                                              BELDEN INC.



Date: May 8, 2001              By:          /s/ C. Baker Cunningham
                                     ------------------------------------
                                        C. Baker Cunningham
                                          Chairman of the Board, President
                                            and Chief Executive Officer





Date: May 8, 2001              By:               /s/ Paul Schlessman
                                     -------------------------------------
                                            Paul Schlessman
                                            Vice President, Finance,
                                                and Chief Financial Officer


                                      -18-