<PAGE>
================================================================================

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

                                    Form 10-Q

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

                  For the quarterly period ended June 30, 2001

                                       OR

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

                       (Commission file number: 000-30931)

                            OPNET TECHNOLOGIES, INC.
             (Exact name of registrant as specified in its charter)

          Delaware                        7373                   52-1483235
(State or other jurisdiction  (Primary Standard Industrial    (I.R.S. Employer
    of incorporation or        Classification Code Number)   Identification No.)
       organization)

                              7255 Woodmont Avenue
                               Bethesda, MD 20814
                     (Address of principal executive office)

                                 (240) 497-3000
              (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
registrants were required to file such reports), and (2) has been subject to
such filing requirements for the past 90 days. Yes [X] No [ ]

    At August 8, 2001, there were outstanding 18,965,132 shares of common stock
of the registrant.

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

<PAGE>

                                TABLE OF CONTENTS
<TABLE>
<CAPTION>
                                                                                                 Page
                                                                                                 ----
<S>      <C>                                                                                     <C>
PART I.  FINANCIAL INFORMATION

Item 1.  Consolidated Financial Statements                                                          3

         Consolidated Balance Sheets as of June 30 and March 31, 2001                               3

         Consolidated Statements of Operations for the Three Months Ended June 30, 2001 and 2000    4

         Consolidated Statements of Cash Flows for the Three Months Ended June 30, 2001 and 2000    5

         Notes to Consolidated Financial Statements                                                 6

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

Item 3.  Quantitative and Qualitative Disclosures About Market Risk                                17

PART II. OTHER INFORMATION

Item 1.  Legal Proceedings                                                                         18

Item 2.  Changes in Securities and Use of Proceeds                                                 18

Item 3.  Defaults Upon Senior Securities                                                           18

Item 4.  Submission of Matters to a Vote of Security Holders                                       18

Item 5.  Other Information                                                                         18

Item 6.  Exhibits and Reports on Form 8-K                                                          18

         Signatures                                                                                19
</TABLE>

                                       2

<PAGE>

                          PART I. FINANCIAL INFORMATION

ITEM 1. Consolidated Financial Statements

                            OPNET Technologies, Inc.
                           Consolidated Balance Sheets
                      (in thousands, except per share data)

<TABLE>
<CAPTION>
                                                                              June 30,           March 31,
                                                                                2001               2001
                                                                          ---------------     ---------------
                                ASSETS                                      (unaudited)          (audited)
<S>                                                                        <C>                 <C>
Current assets:
    Cash and cash equivalents                                              $      60,595       $      62,623
    Accounts receivable, net of $40 and $113 in allowance
        for doubtful accounts at June 30 and March 31, 2001,
        respectively                                                               5,408               4,515
    Unbilled accounts receivable                                                   1,029               1,406
    Refundable income taxes                                                           12                 332
    Deferred income taxes                                                            615                 546
    Prepaid expenses and other current assets                                      1,219               2,486
                                                                          ---------------     ---------------
           Total current assets                                                   68,878              71,908

Property and equipment, net                                                        7,310               6,891
Intangible assets, net                                                             1,900               2,000
Goodwill and assembled workforce                                                  10,921              10,704
Other assets:
    Deposits                                                                          59                  75
    Loan to officer                                                                    -                 231
    Purchased software, net                                                          488                 464
                                                                          ---------------     ---------------
           Total assets                                                    $      89,556       $      92,273
                                                                          ===============     ===============

                      LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities:
    Accounts payable                                                       $         702       $         514
    Accrued liabilities                                                            2,315               7,146
    Accrued income taxes                                                             201                  93
    Deferred revenue                                                               7,686               7,681
                                                                          ---------------     ---------------
           Total current liabilities                                              10,904              15,434

    Deferred rent                                                                    143                  59
    Deferred revenue                                                                 330                 311
    Deferred taxes                                                                    60                  15
                                                                          ---------------     ---------------
           Total liabilities                                                      11,437              15,819
                                                                          ---------------     ---------------
Commitments and contingencies
Stockholders' equity:
    Preferred stock-par value $0.001; 5,000 shares authorized; 160
        designated as Series A (above), No shares issued and outstanding
        at June 30 and March 31, 2001                                                  -                   -
    Common stock-par value $0.001; 100,000 authorized; 25,025 and 24,901
        shares issued at June 30 and March 31, 2001, respectively; 18,891
        and 18,767 shares outstanding at June 30 and March 31, 2001,
        respectively                                                                  25                  25
    Additional paid-in capital                                                    71,182              70,708
    Deferred compensation                                                           (158)               (180)
    Retained earnings                                                             11,174               9,999
    Accumulated other comprehensive (loss) income                                     (4)                  2
    Treasury stock-6,134 shares at June 30 and March 31, 2001                     (4,100)             (4,100)
                                                                          ---------------     ---------------
           Total stockholders' equity                                             78,119              76,454
                                                                          ---------------     ---------------
           Total liabilities and stockholders' equity                      $      89,556       $      92,273
                                                                          ===============     ===============
</TABLE>
                 See notes to consolidated financial statements.

                                       3

<PAGE>
                            OPNET Technologies, Inc.
                      Consolidated Statements of Operations
                                   (unaudited)

<TABLE>
<CAPTION>
                                                              Three Months Ended
                                                                   June 30,
                                                         ------------------------------
                                                             2001              2000
                                                         ------------     -------------
                                                      (in thousands, except per share data)
<S>                                                        <C>               <C>
Revenues:
    Software licenses                                      $   6,530         $   3,653
    Services                                                   4,600             2,781
                                                         ------------     -------------
               Total revenues                                 11,130             6,434
                                                         ------------     -------------
Cost of revenues:
    Software licenses                                            110               177
    Services                                                   1,519               987
                                                         ------------     -------------
               Total cost of revenues                          1,629             1,164
                                                         ------------     -------------
Gross profit                                                   9,501             5,270
                                                         ------------     -------------
Operating expenses:
    Research and development                                   3,154             1,682
    Sales and marketing                                        4,169             2,715
    General and administrative                                   985               660
    Amortization of acquired technology                          100                 -
                                                         ------------     -------------
               Total operating expenses                        8,408             5,057
                                                         ------------     -------------
Income from operations                                         1,093               213
Interest and other income                                        651               136
                                                         ------------     -------------
Income before provision for income taxes                       1,744               349
Provision for income taxes                                       569               125
                                                         ------------     -------------
Net income                                                     1,175               224
Accretion of transaction costs on redeemable convertible
    preferred stock                                                -                (4)
                                                         ------------     -------------
Net income applicable to common shares                     $   1,175          $    220
                                                         ============     =============
Basic net income per common share                          $    0.06          $   0.02
                                                         ============     =============
Diluted net income per common share                        $    0.06          $   0.02
                                                         ============     =============
Weighted average common shares outstanding (basic)            18,809            13,292
                                                         ============     =============
Weighted average common shares outstanding (diluted)          20,238            14,636
                                                         ============     =============
</TABLE>

                 See notes to consolidated financial statements.

                                       4

<PAGE>
                            OPNET Technologies, Inc.
                      Consolidated Statements of Cash Flows
                                   (unaudited)

<TABLE>
<CAPTION>
                                                                         Three Months Ended
                                                                               June 30,
                                                                  -------------------------------
                                                                       2001              2000
                                                                  --------------     ------------
                                                                           (in thousands)
<S>                                                               <C>                <C>
Cash flows from operating activities:
    Net income                                                    $       1,175      $        224
    Adjustments to reconcile net income to net cash provided by
        operating activities:
        Depreciation and amortization                                       500               353
        Deferred income taxes                                               (24)              (80)
        Tax benefit from exercise of nonqualified stock options              53                 -
        Expense related to employee stock options                            22                24
        Changes in assets and liabilities:
           Accounts receivable                                             (747)              122
           Prepaid expenses and other current assets                        844               (13)
           Loans to employees                                               231                 -
           Refundable income taxes                                          320                 5
           Deposits                                                          16                (3)
           Accounts payable                                                 188               (70)
           Accrued liabilities                                           (2,284)             (579)
           Accrued income taxes                                             108                 -
           Deferred revenue                                                  24               467
           Deferred rent                                                     84                 1
                                                                  --------------     ------------
             Net cash provided by operating activities                      510               451
                                                                  --------------     ------------
Cash flows from investing activities:
    Acquisition                                                          (1,156)                -
    Purchase of software                                                    (24)              (15)
    Purchase of property and equipment                                   (1,773)             (325)
                                                                  --------------     ------------
             Net cash used in investing activities                       (2,953)             (340)
                                                                  --------------     ------------
Cash flows from financing activities:
    Costs incurred for initial public offering                                -              (330)
    Proceeds from exercise of common stock options                          212               285
    Proceeds from issuance of common stock under employee stock
        purchase plans                                                      209                 -
                                                                  --------------     ------------
             Net cash provided by financing activities                      421               (45)
                                                                  --------------     ------------

Effect of exchange rate changes on cash and cash equivalents                 (6)                -

Net (decrease) increase in cash and cash equivalents                     (2,028)               66

Cash and cash equivalents, beginning of period                           62,623             8,765
                                                                  --------------     ------------
Cash and cash equivalents, end of period                          $      60,595      $      8,831
                                                                  ==============     ============
</TABLE>

                 See notes to consolidated financial statements.

                                       5

<PAGE>
                            OPNET Technologies, Inc.
                   Notes to Consolidated Financial Statements
                                   (unaudited)

    1. Basis of Presentation and Nature of Operations

    OPNET Technologies, Inc. ("OPNET", the "Company", "we" or "us") provides
intelligent network management software solutions that enable organizations to
optimize the performance and maximize the availability of communications
networks and networked applications. The OPNET product suite combines predictive
modeling and a comprehensive understanding of networking technologies to enable
network professionals to more effectively design and deploy networks, provision
services, diagnose network and application performance problems, predict the
impact of network changes, and efficiently plan capital investments. OPNET is
headquartered in Bethesda, Maryland and has sales offices worldwide.

    The accompanying consolidated financial statements include the results of
OPNET Technologies, Inc. and its wholly-owned subsidiaries. All significant
intercompany accounts and transactions have been eliminated in consolidation.
The interim financial statements included herein are unaudited and have been
prepared in accordance with generally accepted accounting principles ("GAAP")
and applicable rules and regulations of the Securities and Exchange Commission
(the "SEC") regarding interim financial reporting. Certain information and
footnote disclosures normally included in financial statements prepared in
accordance with GAAP have been condensed or omitted pursuant to such rules and
regulations. Accordingly, these interim financial statements should be read in
conjunction with the audited consolidated financial statements and accompanying
notes thereto contained in the Company's Annual Report on Form 10-K for the year
ended March 31, 2001, filed with the SEC. In the opinion of management, these
interim financial statements reflect all adjustments of a normal and recurring
nature necessary to present fairly the Company's results for the interim
periods. The preparation of financial statements in conformity with GAAP
requires management to make certain estimates and assumptions. These estimates
and assumptions affect the reported amounts of assets and liabilities as of the
date of the financial statements, as well as the reported amount of revenues and
expenses during the reporting period. Actual results could differ from those
estimates. In addition, the Company's operating results for the three months
ended June 30, 2001 may not be indicative of the operating results for the full
fiscal year or any other future period.

    On March 30, 2001, OPNET Development Corp., a wholly-owned subsidiary of the
Company, acquired substantially all of the assets and operations of the NetMaker
Division of Make Systems, Inc. ("NetMaker") using the purchase method of
accounting. NetMaker offers a sophisticated suite of products that address the
operational and engineering needs of traditional and next-generation network
service providers. The results of NetMaker's operations have been included in
the accompanying consolidated statements of operations from the date of
acquisition.

    2. Credit Agreements

    In June 2000, the Company entered into a $5,000,000 line of credit facility
with a commercial bank. The line of credit allowed the Company to use the funds
for corporate borrowings and the issuance of letters of credit up to a maximum
of $5,000,000. The Company used the facility to issue a letter of credit for
approximately $3,400,000 to satisfy the security deposit requirements for its
new corporate office facilities lease. The Company renewed the credit facility
for an additional year, and it will now expire in June 2002. Interest is payable
monthly, based on LIBOR plus the applicable margin ranging from 2% to 2.5% as
stated in the loan agreement. The credit facility is collateralized by certain
assets of the Company and there are also certain financial ratios and conditions
that the Company must maintain under the terms of the loan agreement, as well as
certain covenants with which the Company must comply. As of June 30, 2001, the
Company had no balance outstanding under its line of credit.

    3. Stockholders' Equity

    During the three months ended June 30, 2001, employee exercises of stock
options resulted in proceeds to the Company of approximately $212,000 and the
issuance of 104,544 shares of Common Stock. Employee purchases of Common Stock
under the 2000 Employee Stock Purchase Plan resulted in further proceeds to the
Company of approximately $209,000 and the issuance of 19,111 shares of Common
Stock during the three months ended June 30, 2001.


                                       6

<PAGE>

    4. Net Income Per Common Share

    In February 1997, the Financial Accounting Standards Board ("FASB") issued
Statement of Financial Accounting Standard ("SFAS") No. 128, Earnings Per Share.
This statement requires dual presentation of basic and diluted earnings per
share on the face of the income statement. In April 2001, the Emerging Issues
Task Force rendered an interpretation, Topic No. D-95, "Effect of Participating
Convertible Securities on the Computation of Basic Earnings Per Share" which
stipulates that participating convertible securities should be included in the
computation of basic earnings per share. The Company has restated basic earnings
per share for the three months ended June 30, 2000 in accordance with this
interpretation. The effect on basic earnings per share was a $0.01 reduction for
the quarter ended June 30, 2000. Basic earnings per share is to be computed by
dividing net income available to common shareholders by the weighted average
number of common shares and participating preferred shares outstanding for the
period. Diluted earnings per share is to reflect the potential dilution that
could occur if securities or other contracts to issue common shares were
exercised or converted into common shares.

<TABLE>
<CAPTION>
                                                                       Three Months Ended
                                                                            June 30,
                                                                    ------------------------
                                                                       2001           2000
                                                                    ----------    ----------
<S>                                                                 <C>            <C>
                                                                     (in thousands, except
                                                                        per share data)
Income (Numerator):
      Net income applicable to common shares                        $   1,175      $    220
      Plus:
      Accretion of transaction costs on redeemable convertible
          preferred stock                                                   -             4
                                                                    ----------    ----------
      Net income (basic and diluted)                                $   1,175      $    224
                                                                    ==========    ==========
Shares (Denominator):
      Weighted average shares outstanding                              18,809        11,120
      Plus:
           Participating redeemable convertible preferred stock             -         2,172
                                                                    ----------    ----------
      Weighted average shares outstanding (basic)                      18,809        13,292
      Plus:
           Effect of other dilutive securities - Options                1,429         1,344
                                                                    ----------    ----------
      Weighted average shares outstanding (diluted)                    20,238        14,636
                                                                    ==========    ==========
Net income per common share:
      Basic net income per common share                              $   0.06     $    0.02
      Diluted net income per common share                            $   0.06     $    0.02
</TABLE>

    5. Business Segment and Geographic Area Information

    The Company operates in one industry segment, the development and sale of
computer software programs and related services. There were no sales to any
customers within a single country except for the United States where such sales
accounted for 10% or more of total revenues. Substantially all assets were held
in the United States for the quarter ended June 30, 2001.

    6. Supplemental Cash Flow Information
                                                         Three Months Ended
                                                               June 30,
                                                      -------------------------
                                                        2001             2000
                                                      --------           ------
Supplemental disclosure of cash flow information:           (in thousands)
     Cash paid during the year for income taxes       $    105           $    3

Supplemental disclosure of non cash activities:

     Accrued tenant allowance                         $    423           $    -
     Post-closing acquisition adjustments             $    217           $    -
     Accrued offering costs                           $      -           $  524
     Accretion on preferred stock                     $      -           $    4

                                       7

<PAGE>

    7. Comprehensive Income

    In June 1997, the FASB issued SFAS No. 130, Reporting Comprehensive Income.
This statement requires the Company to report and display certain information
related to comprehensive income and its components. Comprehensive income
includes net income and other comprehensive income. For the three months ended
June 30, 2001, comprehensive income for the Company was $1.2 million, and
included accumulated foreign currency translation losses of approximately
$6,000.

    8. New Accounting Pronouncements

    In July 2001, the FASB issued SFAS No. 141, Business Combinations, and SFAS
No. 142, Goodwill and Other Intangible Assets. SFAS No. 141 requires business
combinations initiated after June 30, 2001 to be accounted for using the
purchase method of accounting, and that certain acquired intangible assets in a
business combination be separately identified and recognized as assets apart
from goodwill. SFAS No. 142 requires that goodwill and certain other intangible
assets will no longer be amortized and instead will be subject to periodic
evaluation for impairment. In addition, the standard includes provisions for the
reclassification of certain existing recognized intangibles as goodwill.

     The Company has elected for early adoption of SFAS No. 141 and 142, which
is permitted for entities with fiscal years beginning after March 15, 2001. As a
result, the Company has not amortized approximately $10.0 million of goodwill
and $950,000 of assembled workforce acquired in connection with the NetMaker
acquisition, which closed on March 30, 2001. During the three months ended June
30, 2001, goodwill was adjusted by approximately $217,000 for modifications to
initial purchase accounting estimates. Also in connection with the NetMaker
acquisition we recorded acquired technology of $2.0 million, which is being
amortized on a straight-line basis over a period of five years. Amortization of
acquired technology for the three months ended June 30, 2001 was $100,000. We
expect amortization expense of approximately $400,000 in each of the fiscal
years ended March 31, 2002, 2003, 2004, 2005 and 2006, relating to the acquired
technology.

                                                    As of June 30, 2001
                                            ----------------------------------
                                            Gross Carrying        Accumulated
                                                Amount            Amortization
                                            --------------        ------------
                                                      (in thousands)
Amortized intangible assets
     Acquired technology                      $     2,000          $      100
                                            ==============        ============

Unamortized intangible assets
     Goodwill                                       9,971
     Assembled workforce                              950
                                            --------------
        Total                                 $    10,921
                                            ==============

    9. Subsequent Events

     In August 2001, the Company entered into an agreement with Comsof N.V. to
form a joint venture, WDM NetDesign B.V.B.A. ("WDM NetDesign"), in which the
companies will collaborate on the development of optical network planning
products. Under the agreement, OPNET acquired a 20% interest in WDM NetDesign
for consideration of $399,000 and purchased an option for consideration of
$1,000 to acquire all remaining shares of WDM NetDesign. If the Company
exercises the option, OPNET will acquire the remaining shares for a total
consideration of $1,325,000 to be paid in cash or a combination of cash and
OPNET common stock. The option expires in December 2001.


                                       8

<PAGE>

    ITEM 2. Management's Discussion and Analysis of Financial Condition and
Results of Operations

    The following discussion and analysis relates to the financial condition and
results of operations of the Company for the three months ended June 30, 2001,
and should be read in conjunction with "Management's Discussion and Analysis of
Financial Condition and Results of Operations" contained in the Company's Annual
Report on Form 10-K for the year ended March 31, 2001, filed with the SEC.

    This report contains forward-looking statements that involve substantial
risks and uncertainties. The statements contained in this report that are not
purely historical are forward-looking statements within the meaning of Section
27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act
of 1934. You can identify these statements by forward-looking words such as
"anticipate," "believe," "could," "estimate," "expect," "intend," "may," "plan,"
"potential," "should," "will," and "would" or similar words. You should read
statements that contain these words carefully because they discuss our future
expectations, contain projections of our future results of operations or of our
financial position or state other forward-looking information. We believe that
it is important to communicate our future expectations to our investors.
However, there may be events in the future that we are not able to predict or
control accurately. The factors listed below in the section captioned "Certain
Factors That May Affect Future Results," as well as any cautionary language
contained herein, provide examples of risks, uncertainties, and events that may
cause our actual results to differ materially from the expectations we describe
in our forward-looking statements. Further, any forward-looking statement speaks
only as of the date on which such statement is made, and we undertake no
obligation to publicly update or revise any forward-looking information.

    Overview

    We provide intelligent network management software products and related
services. Our product suite consists of four primary software products: OPNET IT
Guru, OPNET Modeler, OPNET Netbiz, and our newest product, OPNET ServiceProvider
Guru (released in June 2001). We sell our OPNET suite of products to service
providers, including telecommunications carriers; ISPs and ASPs; large and
medium-sized enterprises; and network equipment manufacturers. We market our
product suite in North America primarily through a direct sales force and, to a
lesser extent, several resellers and original equipment manufacturers.
Internationally, we market our products primarily through our international
subsidiaries and third-party distributors.

    We sold our first products in 1987. Our operations, including acquisitions,
have been financed principally through cash provided by operations, a venture
financing in September 1997 and the proceeds of our initial public offering in
August 2000. In August 1998, we introduced our OPNET IT Guru and OPNET Netbiz
products. In June 2001, we released OPNET ServiceProvider Guru and began a new
marketing and sales strategy to focus on this product.

    We generate revenues principally from licensing our software products and
providing related services, including maintenance and technical support,
consulting, and training.

    Our software license revenues consist of perpetual and term license sales of
our software products and royalty income. Software license revenues are
recognized upon delivery, provided that fees are fixed and determinable, no
significant modifications to the product are required, and collection of the
related receivable is probable. Where significant modifications are required,
software license revenues are recognized along with consulting fees on a
percentage-of-completion basis as the modifications are performed. We allow
customers to evaluate our software before purchase, and therefore it is our
policy not to allow returns.

    Our service revenues consist of fees from maintenance and technical support
agreements, consulting services, and training. The maintenance agreements
covering our products provide for technical support and periodic product
upgrades. Revenues from maintenance and technical support agreements are
deferred and recognized ratably over the support period. We offer consulting
services primarily to provide product customization and enhancements. Consulting
services are generally performed under fixed-price agreements and recognized as
the work is performed on a percentage-of-completion basis. We provide classroom
and on-site training to our customers on a daily fee basis.

    Software license revenues and service revenues for which payment has been
received, but that do not yet qualify for recognition as revenues, are reflected
as deferred revenues.


                                       9

<PAGE>

    Results of Operations

    The following table sets forth items from our statements of operations
expressed as a percentage of total revenues for the periods indicated:

                                                        Three Months Ended
                                                             June 30,
                                                      ------------------------
                                                          2001          2000
                                                      ----------   -----------
Revenues:
    Software licenses                                      58.7 %        56.8 %
    Services                                               41.3          43.2
                                                      ----------   -----------
       Total revenues                                     100.0         100.0
                                                      ----------   -----------
Cost of revenues:
    Software licenses                                       1.0           2.8
    Services                                               13.6          15.3
                                                      ----------   -----------
       Total cost of revenues                              14.6          18.1
                                                      ----------   -----------
Gross profit                                               85.4          81.9
                                                      ----------   -----------
Operating expenses:
    Research and development                               28.3          26.1
    Sales and marketing                                    37.5          42.2
    General and administrative                              8.8          10.3
    Amortization of acquired technology                     0.9             -
                                                      ----------   -----------
       Total operating expenses                            75.5          78.6
                                                      ----------   -----------
Income from operations                                      9.9           3.3
Interest and other income                                   5.8           2.1
                                                      ----------   -----------
Income before provision for income taxes                   15.7           5.4
Provision for income taxes                                  5.1           1.9
                                                      ----------   -----------
Net income                                                 10.6 %         3.5 %
                                                      ==========   ===========

    The following table sets forth, for each component of revenues, the cost of
these revenues as a percentage of the related revenues for the periods
indicated:

                                                         Three Months Ended
                                                              June 30,
                                                       ------------------------
                                                          2001          2000
                                                       ----------   -----------
    Cost of software license revenues                      1.7 %         4.8 %
    Cost of service revenues                              33.0          35.5

Comparison of Three Months Ended June 30, 2001 and 2000

    Revenues

    Total revenues increased 73.0% to $11.1 million for the three months ended
June 30, 2001 from $6.4 million for the three months ended June 30, 2000. We
believe that the percentage increase in our total revenues achieved in this
period is not necessarily indicative of future results. Software license
revenues were 58.7% and 56.8% of total revenues for the three months ended June
30, 2001 and 2000, respectively.

    Software License Revenues. Software license revenues increased 78.8% to $6.5
million for the three months ended June 30, 2001 from $3.7 million for the three
months ended June 30, 2000. The increase was primarily attributable to the
substantial growth in overall demand for our suite of products and broadening
portfolio of related models and modules, increase in the average transaction
size, expansion of our marketing and direct sales force and the continued growth
of our international presence.


                                       10

<PAGE>

    Service Revenues. Service revenues increased 65.4% to $4.6 million for the
three months ended June 30, 2001 from $2.8 million for the three months ended
June 30, 2000. This growth in service revenues was primarily a result of
increased maintenance and technical support contracts related to new license
sales, increased renewals of maintenance and technical support contracts by our
installed base of customers, and growing demand for consulting services,
primarily for the customization of our OPNET Netbiz product.

    Cost of Revenues

    Cost of software license revenues consists primarily of royalties, media,
manuals, and distribution costs. Cost of service revenues consists primarily of
personnel-related costs in providing maintenance and technical support,
consulting, and training to customers. Gross margin on software license revenues
is substantially higher than gross margin on service revenues, reflecting the
low materials, packaging, and other costs of software products compared with the
relatively high personnel costs associated with providing services. Cost of
service revenues varies based upon the relative mix of maintenance and technical
support, consulting, and training services.

    Cost of Software License Revenues. Cost of software license revenues
decreased 37.9% to $110,000 for the three months ended June 30, 2001 from
$177,000 for the three months ended June 30, 2000. Gross margin on software
license revenues increased to 98.3% for the three months ended June 30, 2001
from 95.2% for the three months ended June 30, 2000. The decrease in costs of
software license revenues and the related increase in margin was primarily due
to a reduction in the level of sales requiring royalty payments under the March
1999 agreement with Cadence Design Systems that required us to pay a 50% royalty
for specified sales of OPNET Modeler to the portion of Cadence's customer base
that uses an existing Cadence product. This agreement ended on March 31, 2001.

    Cost of Service Revenues. Cost of service revenues increased 53.9% to $1.5
million for the three months ended June 30, 2001 from $987,000 for the three
months ended June 30, 2000. Gross margin on service revenues increased to 67.0%
for the three months ended June 30, 2001 from 64.5% for the three months ended
June 30, 2000. This increase in margin is primarily due to a proportionally
higher level of service revenues derived from maintenance services, which have a
higher gross margin than consulting services.

    Operating Expenses

    Research and Development. Research and development expenses consist
primarily of salaries, related benefits, and other engineering-related costs.
Research and development expenses increased 87.5% to $3.2 million for the three
months ended June 30, 2001 from $1.7 million for the three months ended June 30,
2000. The increase was primarily related to increased research and development
staffing levels as a result of the NetMaker acquisition. As a percentage of
total revenues, research and development expenses increased to 28.3% for the
three months ended June 30, 2001 from 26.1% for the three months ended June 30,
2000. This increase as a percentage of total revenues is primarily due to
increased staffing levels as result of the NetMaker acquisition, and a resulting
increase in costs of research and development programs related to the
development of new products, including the release of OPNET ServiceProvider Guru
in June 2001, and sustaining and upgrading our existing products. We believe
that a significant level of research and development investment will be required
to maintain our competitive advantage, and expect that the dollar amount of
these expenditures will continue to grow in future periods.

    Sales and Marketing. Sales and marketing expenses increased 53.6% to $4.2
million for the three months ended June 30, 2001 from $2.7 million for the three
months ended June 30, 2000. This increase was primarily due to a substantial
increase in the size of our direct sales force, increased commissions associated
with the growth in revenues, and an overall increase in the level of
advertising, tradeshow and other marketing activities. As a percentage of total
revenues, sales and marketing expenses decreased to 37.5% for the three months
ended June 30, 2001 from 42.2% for the three months ended June 30, 2000. This
decrease as a percentage of total revenues resulted from a proportionally
smaller increase in costs associated with developing market awareness for our
newer products relative to the higher level of revenues for the three months
ended June 30, 2001. We intend to continue to expand our global sales and
marketing infrastructure and, accordingly, expect our sales and marketing
expenses to increase in the future.

    General and Administrative. General and administrative expenses consist
primarily of salaries, related benefits, and fees for recruiting, legal,
accounting, and other services. General and administrative expenses increased
49.2% to $985,000 for the three months ended June 30, 2001 from $660,000 for the
three months ended June 30, 2000. The increased level of spending was primarily
due to additional personnel costs and other expenses associated with the
expansion of our supporting infrastructure. As a percentage of total revenues,
general and administrative expenses decreased to 8.8% for the three months ended
June 30, 2001 from 10.3% for the three months ended June 30, 2000. We expect
that the dollar amount of general and administrative expenses will increase as
we expand our operations.

                                       11

<PAGE>
    Amortization of Acquired Technology. In connection with the NetMaker
acquisition, we recorded acquired technology of $2.0 million, which is being
amortized on a straight-line basis over a period of five years. Amortization of
acquired technology for the three months ended June 30, 2001 was $100,000. We
expect amortization expense of approximately $400,000 in each of the fiscal
years ended March 31, 2002, 2003, 2004, 2005 and 2006, relating to the acquired
technology.

    Interest and Other Income

    Interest and other income increased to $651,000 for the three months ended
June 30, 2001 from $136,000 for the three months ended June 30, 2000. The
increase was primarily due to interest earned on the proceeds from our initial
public offering and to a lesser extent, the contribution of additional cash
produced by our operations offset by fees associated with our $3.4 million
letter of credit outstanding at June 30, 2001.

    Provision for Income Taxes

    The provision for income taxes increased to $569,000 for the three months
ended June 30, 2001 from $125,000 for the three months ended June 30, 2000. Our
effective tax rate for the three months ended June 30, 2001 was 32.6% compared
to 35.8% for the three months ended June 30, 2000. This increase in the
provision and corresponding decrease in the effective tax rate is primarily due
to the growth in operating income partially offset by an increased percentage of
research and development tax credits available to us.

    Liquidity and Capital Resources

    Since inception, we have funded our operations primarily through cash
provided by operating activities. In September 1997, we raised $7.0 million in
venture financing, of which we used $3.4 million to repurchase stock from our
existing stockholders. In August 2000, we completed our initial public offering
in which we raised approximately $54.1 million, net of underwriting discounts
and commissions and estimated offering expenses paid by us. As of June 30, 2001,
we had cash and cash equivalents totaling $60.6 million.

    Cash provided by operating activities was $510,000 for the three months
ended June 30, 2001. Cash provided by operating activities is primarily derived
from net income, as adjusted for depreciation and amortization. Cash used in
investing activities was $3.0 million for the three months ended June 30, 2001.
The funds were used primarily to purchase property and equipment for our new
corporate headquarters in Bethesda, Maryland and to pay the costs incurred for
the NetMaker acquisition. Cash provided by financing activities was $421,000 for
the three months ended June 30, 2001, reflecting the proceeds received from the
exercise of stock options and the sale of common stock under our 2000 Employee
Stock Purchase Plan.

    We have a $5.0 million revolving line of credit with a commercial bank,
which expires in June 2002. Borrowings under this line of credit bear interest
an annual rate equal to LIBOR plus 2% to 2.5%. We have currently used $3.4
million of this facility for a letter of credit that secures the lease for our
new headquarters in Bethesda, Maryland.

    We expect to experience growth in our working capital needs for the
foreseeable future as we execute our business plan. We anticipate that operating
activities, as well as planned capital expenditures, will constitute a material
use of our cash resources. We recently entered into a new headquarters lease
agreement which will increase our facilities costs. In addition, we may utilize
cash resources to further expand the facility, or to fund acquisitions or
investments in complementary businesses, technologies, or products.

    We believe that our current cash and cash equivalents and cash generated
from operations, along with available borrowings under our line of credit, will
be sufficient to meet our anticipated cash requirements for working capital and
capital expenditures for at least the next 12 months.

    Certain Factors That May Affect Future Results

    The following important factors, among others, could cause actual results to
differ materially from those indicated by forward-looking statements made in
this Annual Report and presented elsewhere by management from time to time.

    Our operating results may fluctuate significantly as a result of factors
outside of our control, which could cause the market price of our stock to
decline.

    Our operating results have fluctuated in the past, and are likely to
fluctuate significantly in the future. Our financial results may as a
consequence fall short of the expectations of public market analysts or
investors, which could cause the price of our common stock to

                                       12

<PAGE>

decline. Our revenues and operating results may vary significantly from quarter
to quarter due to a number of factors, many of which are beyond our control.
Factors that could affect our operating results include:

        o   the timing of large orders;

        o   changes in the mix of our sales, including the mix between higher
            margin software products and somewhat lower margin services and
            maintenance, and the proportion of our license sales requiring us to
            make royalty payments;

        o   the timing and amount of our marketing, sales, and product
            development expenses;

        o   the cost and time required to develop new software products;

        o   the introduction, timing, and market acceptance of new products
            introduced by us or our competitors;

        o   changes in network technology or in applications, which could
            require us to modify our products or develop new products;

        o   general economic conditions, which can affect our customers'
            purchasing decisions and the length of our sales cycle;

        o   changes in our pricing policies or those of our competitors; and

        o   the timing and size of potential acquisitions by us.

    We expect to make significant expenditures in all areas of our business,
particularly sales and marketing operations, in order to promote future growth.
Because the expenses associated with these activities are relatively fixed in
the short term, we may be unable to adjust spending quickly enough to offset any
unexpected shortfall in revenue growth or any decrease in revenue levels. In
addition, our revenues in any quarter depend substantially on orders we receive
and ship in that quarter. We typically receive a significant portion of orders
in any quarter during the last month of the quarter, and we cannot predict
whether those orders will be placed and shipped in that period. If we have lower
revenues than we expect, we probably will not be able to reduce our operating
expenses quickly in response. Therefore, any significant shortfall in revenues
or delay of customer orders could have an immediate adverse effect on our
operating results in that quarter.

    For all of these reasons, quarterly comparisons of our financial results are
not necessarily meaningful and you should not rely on them as an indication of
our future performance.

    The market for intelligent network management software is new and evolving,
and if this market does not develop as anticipated, our revenues could decline

    We derive all of our revenues from the sale of products and services that
are designed to allow our customers to manage the performance of networks and
applications. Accordingly, if the market for intelligent network management
software does not continue to grow, we could face declining revenues, which
could ultimately lead to our becoming unprofitable. The market for intelligent
network management software solutions is in an early stage of development.
Therefore, we cannot accurately assess the size of the market and may be unable
to identify an effective distribution strategy, the competitive environment that
will develop, and the appropriate features and prices for products to address
the market. If we are to be successful, our current and potential customers must
recognize the value of intelligent network management software solutions, decide
to invest in the management of their networks, and, in particular, adopt and
continue to use our software solutions.

    We may not be able to grow our business if service providers do not buy our
products

    A key element of our strategy is to increase sales to service providers, and
our future performance will be significantly dependent upon increased adoption
by service providers of our software products, including OPNET ServiceProvider
Guru. Accordingly, the failure of our products to perform favorably in the
service provider environment or to gain wider adoption by service providers
could have a negative effect on our business and future operating results.

    If our newest products, OPNET IT Guru, OPNET Netbiz and OPNET
ServiceProvider Guru, do not gain widespread market acceptance, our revenues
might not increase and could even decline

    We expect to derive a substantial portion of our revenues in the future from
OPNET IT Guru and OPNET Netbiz, both of which were released in August 1998, and
OPNET ServiceProvider Guru, which was released in June 2001. Our business
depends on

                                       13

<PAGE>

customer acceptance of these products and our revenues may not increase, or may
decline, if our target customers do not adopt and expand their use of OPNET IT
Guru, OPNET Netbiz and OPNET ServiceProvider Guru. To date, we have not achieved
widespread market acceptance of either OPNET IT Guru or OPNET Netbiz, and we
have only recently begun shipping OPNET ServiceProvider Guru. In addition, if
our OPNET Modeler product, which we have been selling since 1987, encounters
declining sales, which could occur for a variety of reasons, including market
saturation, and sales of our newer products do not grow at a rate sufficient to
offset the shortfall, our revenues would decline.

    If we do not successfully expand our sales force, we may be unable to
increase our sales

    We sell our products primarily through our direct sales force, and we must
expand the size of our sales force to increase revenues. If we are unable to
hire or retain qualified sales personnel, if newly hired personnel fail to
develop the necessary skills to be productive, or if they reach productivity
more slowly than anticipated, our ability to increase our revenues and grow our
business could be compromised. Our sales people require a long period of time to
become productive, typically three to six months. The time required to reach
productivity, as well as the challenge of attracting, training, and retaining
qualified candidates, may make it difficult to meet our sales force growth
targets. Further, we may not generate sufficient sales to offset the increased
expense resulting from growing our sales force or we may be unable to manage a
larger sales force.

    Our ability to increase our sales will be impaired if we do not expand and
manage our indirect distribution channels

    To increase our sales, we must, among other things, further expand and
manage our indirect distribution channels, which consist primarily of
international distributors and original equipment manufacturers and resellers.
If we are unable to expand and manage our relationships with our distributors,
our distributors are unable or unwilling to effectively market and sell our
products, or we lose existing distributor relationships, we might not be able to
increase our revenues. Our international distributors and original equipment
manufacturers and resellers have no obligation to market or purchase our
products. In addition, they could partner with our competitors, bundle or resell
competitors' products, or internally develop products that compete with our
products.

    We may not be able to successfully manage our expanding operations, which
could impair our ability to operate profitably

    We may be unable to operate our business profitably if we fail to manage our
growth. Our rapid growth has sometimes strained, and may in the future continue
to strain, our managerial, administrative, operational, and financial resources
and controls. We plan to continue to expand our operations and increase the
number of our full-time employees. Our ability to manage growth will depend in
part on our ability to continue to enhance our operating, financial, and
management information systems. Our personnel, systems, and controls may not be
adequate to support our growth. In addition, our revenues may not continue to
grow at a sufficient rate to absorb the costs associated with a larger overall
employee base.

    If we are unable to introduce new and enhanced products on a timely basis
that respond effectively to changing technology, our revenues may decline

    Our market is characterized by rapid technological change, changes in
customer requirements, frequent new product and service introductions and
enhancements, and evolving industry standards. If we fail to develop and
introduce new and enhanced products on a timely basis that respond to these
changes, our products could become obsolete, demand for our products could
decline and our revenues could fall. Advances in network management technology,
software engineering, simulation technology, or the emergence of new industry
standards, could lead to new competitive products that have better performance,
more features, or lower prices than our products and could render our products
unmarketable. In addition, the introduction and adoption of future network
technologies or application architectures could reduce or eliminate the need for
predictive network management software.

    If we fail to retain our key personnel and attract and retain additional
qualified personnel, we might not be able to sustain our revenue growth

    Our future success and our ability to sustain our revenue growth depend upon
the continued service of our executive officers and other key sales and research
and development personnel. The loss of any of our key employees, in particular
Marc A. Cohen, our chairman of the board and chief executive officer, and Alain
J. Cohen, our president and chief technology officer, could adversely affect our
ability to pursue our growth strategy. We do not have employment agreements or
any other agreements that obligate any of our officers or key employees to
remain with us.

    We must also continue to hire large numbers of highly qualified individuals,
particularly software engineers and sales and marketing personnel. Our failure
to attract and retain technical personnel for our product development,
consulting services, and technical support teams may limit our ability to
develop new products or product enhancements. Competition for these individuals
is

                                       14

<PAGE>

intense, and we may not be able to attract and retain additional highly
qualified personnel in the future. In addition, limitations imposed by federal
immigration laws and the availability of visas could impair our ability to
recruit and employ skilled technical professionals from other countries to work
in the United States.

    Our international operations subject our business to additional risks, which
could cause our sales or profitability to decline

    We plan to continue to increase our international sales activities, but
these plans are subject to a number of risks that could cause our sales to
decline or could otherwise cause a decline in profitability. These risks
include:

        o   greater difficulty in accounts receivable collection and longer
            collection periods;

        o   political and economic instability;

        o   difficulty in attracting distributors that will market and support
            our products effectively;

        o   the need to comply with varying employment policies and regulations
            that could make it more difficult and expensive to manage our
            employees if we need to establish more direct sales or support staff
            outside the United States;

        o   potentially adverse tax consequences; and

        o   the effects of currency fluctuations.

    Expanding our OPNET Netbiz consulting services business will be costly and
may not result in any compensating increase in sales or profitability

    We have been aggressively expanding our consulting services delivered in
conjunction with sales of OPNET Netbiz. The significant additional expenditures
and operational resources required to expand our OPNET Netbiz consulting
services business will place additional strain on our management, financial, and
operational resources and may make it more difficult for us to maintain
profitability. If OPNET Netbiz does not achieve significant market acceptance,
our customers will not engage our consulting services organization to assist
with consulting, custom development, implementation support, and training for
OPNET Netbiz. In addition, we may be unable to attract or retain a sufficient
number of the highly qualified consulting services personnel that we expect the
expansion of our consulting services business will require.

    We face intense competition, which could cause us to lose sales, resulting
in lower revenues and profitability

    The intense and increasing competition in our market could cause us to lose
sales, which could result in lower revenues and could cause us to become
unprofitable. The market for intelligent network management software is evolving
rapidly and is highly competitive. We believe that this market is likely to
become more competitive as the demand for intelligent network management
solutions continues to increase. Many of our current and potential competitors
are larger and have substantially greater financial and technical resources than
we do. In addition, it is possible that other vendors as well as some of our
customers or distributors will develop and market solutions that compete with
our products in the future.

     OPNET Modeler, OPNET IT Guru, and OPNET ServiceProvider Guru currently face
or potentially will face competition from several sources, including:

        o   software vendors with intelligent network management offerings and
            application performance diagnosis solutions, such as Compuware;

        o   consultants who offer intelligent network management advisory
            services; and

        o   customers who develop their own intelligent network management
            capabilities, either internally or through outsourcing.

    OPNET Netbiz competes with solutions designed to facilitate and automate
sales processes in general.

     If the Internet infrastructure does not grow as currently anticipated,
sales of our OPNET Netbiz product may not grow and our revenues may decline

                                       15

<PAGE>

    Our OPNET Netbiz product addresses a new and emerging market for sales
process automation, including over the Internet, by service providers and
network equipment manufacturers. The failure of this market to develop, or a
delay in the development of this market, would reduce demand for OPNET Netbiz
and cause our revenues to decline. The success of OPNET Netbiz depends
substantially upon the widespread adoption of the Internet as a primary medium
for commerce and business applications. Moreover, critical issues concerning the
commercial use of the Internet, such as security, reliability, cost,
accessibility, and quality of service, remain unresolved and may negatively
affect the growth of Internet use or the attractiveness of commerce and business
communication over the Internet.

    Potential errors in our products and our inability to correct those errors
could harm our reputation and could cause our customers to demand refunds from
us or assert claims for damages against us

    Our software products could contain significant errors or bugs that may
result in:

        o   the loss of or delay in market acceptance and sales of our products;

        o   the delay in introduction of new products;

        o   diversion of our resources;

        o   injury to our reputation; and

        o   increased support costs.

    Bugs may be discovered at any point in a product's life cycle. We expect
that errors in our products will be found in the future, particularly in new
product offerings and new releases of our current products.

    Because our customers use our products to manage networks that are critical
to their business operations, any failure of our products could expose us to
product liability claims. In addition, errors in our products could cause our
customers' networks and systems to fail or compromise their data, which could
also result in liability to us. Product liability claims brought against us
could divert the attention of management and key personnel, could be expensive
to defend, and may result in adverse settlements and judgments.

    Our software products rely on our intellectual property, and any failure to
protect our intellectual property could enable our competitors to market
products with similar features that may reduce our revenues by decreasing demand
for our products, and could allow the use of our products by users who have not
paid the required license fee

    If we are unable to protect our intellectual property, our competitors could
use our intellectual property to market products similar to our products, which
could reduce our revenues by decreasing demand for our products. In addition, we
may be unable to prevent the use of our products by persons who have not paid
the required license fee, which could reduce our revenues. Our success and
ability to compete depend substantially upon the internally developed technology
that is incorporated in our products. Policing unauthorized use of our products
is difficult, and we may not be able to prevent misappropriation of our
technology, particularly in foreign countries where the laws may not protect our
proprietary rights as fully as those in the United States. Others may circumvent
the patents, copyrights, and trade secrets we own. In the ordinary course of
business, we enter into a combination of confidentiality, non-competition, and
non-disclosure agreements with our employees. These measures afford only limited
protection and may be inadequate, especially because our employees are highly
sought after and may leave our employ with significant knowledge of our
proprietary information. In addition, any confidentiality, non-competition, and
non-disclosure agreements we enter into may be found to be unenforceable, or our
copy protection mechanisms embedded in our software products could fail or could
be circumvented.

    Our products employ technology that may infringe on the proprietary rights
of others, and, as a result, we could become liable for significant damages

    We expect that our software products may be increasingly subject to
third-party infringement claims as the number of competitors in our industry
segment grows and the functionalities of products in different industry segments
overlap. Regardless of whether these claims have any merit, they could:

        o   be time-consuming to defend;

        o   result in costly litigation;

                                       16

<PAGE>

        o   divert our management's attention and resources;

        o   cause us to cease or delay product shipments; or

        o   require us to enter into royalty or licensing agreements.

    These royalty or licensing agreements may not be available on terms
acceptable to us, if at all. A successful claim of product infringement against
us or our failure or inability to license the infringed or similar technology
could adversely affect our business because we would not be able to sell the
affected product without redeveloping it or incurring significant additional
expense.

    If we undertake acquisitions, they may be expensive and disruptive to our
business and could cause the market price of our common stock to decline

    In March 2001, we completed the NetMaker acquisition. We may continue to
acquire or make investments in companies, products, or technologies if
opportunities arise. Any acquisitions could be expensive, disrupt our ongoing
business, distract our management and employees, and adversely affect our
financial results and the market price of our common stock. We may not be able
to identify suitable acquisition or investment candidates, and if we do identify
suitable candidates, we may not be able to make these acquisitions or
investments on commercially acceptable terms or at all. If we make an
acquisition, we could have difficulty integrating the acquired technology,
employees, or operations. In addition, the key personnel of the acquired company
may decide not to work for us. We also expect that we would incur substantial
expenses if we acquired other businesses or technologies. We might use cash on
hand, incur debt, or issue equity securities to pay for any future acquisitions.
If we issue additional equity securities, our stockholders could experience
dilution and the market price of our stock may decline.

    Our products are subject to changing computing environments, including
operating system software and hardware platforms, which could render our
products obsolete

    The evolution of existing computing environments and the introduction of new
popular computing environments may require us to redesign our products or
develop new products. Computing environments, including operating system
software and hardware platforms, are complex and change rapidly. Our products
are designed to operate in currently popular computing environments. Due to the
long development and testing periods required to adapt our products to new or
modified computing environments, we could experience significant delays in
product releases or shipments, which could result in lost revenues and
significant additional expense.

ITEM 3. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK

    We consider all highly liquid investments purchased with a maturity of three
months or less to be cash equivalents, and those with maturities greater than
three months are considered to be marketable securities. Cash equivalents and
marketable securities are stated at amortized cost plus accrued interest, which
approximates fair value. Cash equivalents and marketable securities consist
primarily of money instruments and U.S. Treasury bills. We currently do not
hedge interest rate exposure, but do not believe that an increase in interest
rates would have a material effect on the value of our marketable securities.

                                       17

<PAGE>

                           PART II. OTHER INFORMATION

ITEM 1. Legal Proceedings

    The Company is not party to any material legal proceedings.

ITEM 2. Changes in Securities and Use of Proceeds

    On August 7, 2000, the Company closed an initial public offering of its
Common Stock (the "Offering"). The shares of Common Stock sold in the Offering
were registered under the Securities Act on a Registration Statement on Form S-1
(No. 333-32588) (the "Registration Statement") that was declared effective by
the Securities and Exchange Commission on August 1, 2000, and the Offering
commenced on that date.

    After deducting the underwriting discounts and commissions and the estimated
Offering expenses, the net proceeds to the Company from the Offering were
approximately $54.1 million.

    The Company intends to use the net proceeds of the Offering for general
corporate purposes, including working capital and capital expenditures. From the
date of the Offering through June 30, 2001, the Company used approximately $4.5
million of the net proceeds for capital expenditures and leasehold improvements
related to its new headquarters facility in Bethesda, Maryland. We also used
approximately $6.2 million of the net proceeds for the acquisition and
acquisition-related expenses for the NetMaker division, and $400,000 for the
investment in Comsof. The Company has not allocated any of the remaining net
proceeds to any identifiable uses. The Company may also use a portion of the net
proceeds to acquire businesses, products, or technologies that are complementary
to its business. Pending their use, the Company invests the net proceeds in
investment grade, interest-bearing securities. None of these amounts were paid
directly or indirectly to any director, officer, general partners of the Company
or their associates, persons owning 10% or more of any class of equity
securities of the Company, or any affiliate of the Company.

ITEM 3. Defaults Upon Senior Securities

    None

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

    None

ITEM 5. Other Information

    None

ITEM 6. Exhibits and Reports on Form 8-K

    A. Exhibits

         10.1  Promissory Note, dated June 10, 2001, issued by the Registrant to
               Bank of America, N.A.

    B. Reports on Form 8-K

         On April 4, 2001, the Registrant filed a Current Report on Form 8-K
       under Item 2 (Acquisition or Disposition of Assets) announcing that on
       March 30, 2001 the Registrant completed its previously announced
       acquisition of substantially all of the assets and operations of NetMaker
       pursuant to the Asset Purchase Agreement.

         On June 13, 2001, the Registrant filed an Amendment No. 1 to Current
       Report on Form 8-K/A to file under Item 7 (Financial Statements, Pro
       Forma Financial Information and Exhibits) historical financial statements
       of NetMaker and pro forma financial information reflecting the
       acquisition of NetMaker.

                                       18

<PAGE>

                                   SIGNATURES

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

                                OPNET TECHNOLOGIES, INC.
                                (Registrant)

                                By: /s/ Joseph F. Greeves
                                    ------------------------------------------
                                    Name: Joseph F. Greeves
                                    Title: Senior Vice President and
                                           Chief Financial Officer  (Principal
                                           Financial and Accounting Officer)

Date: August 13, 2001
                                       19