<PAGE>

    As filed with the Securities and Exchange Commission on January 28, 2002
                                                     Registration No. 333-_____
- --------------------------------------------------------------------------------

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D. C. 20549

                                 ______________

                                    Form S-8
                          REGISTRATION STATEMENT UNDER
                           THE SECURITIES ACT OF 1933

                               ___________________

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

                               ___________________
              Delaware                                          52-1483235
   (State or other jurisdiction of                           (I.R.S. Employer
   incorporation or organization)                         Identification Number)

                          ____________________________

                              7255 Woodmont Avenue
                            Bethesda, Maryland 20814
                                 (240) 497-3000
       (Address, including zip code, and telephone number, including area
               code, of registrant's principal executive offices)

                 AMENDED AND RESTATED 2000 STOCK INCENTIVE PLAN
                            (Full title of the Plan)


                                  Marc A. Cohen
                Chairman of the Board and Chief Executive Officer
                            OPNET TECHNOLOGIES, INC.
                              7255 Woodmont Avenue
                            Bethesda, Maryland 20814
                                 (240) 497-3000
     (Name and address, including zip code, and telephone number, including
                        area code, of agent for service)

                         CALCULATION OF REGISTRATION FEE

<TABLE>
<CAPTION>
- -----------------------------------------------------------------------------------------------------------------------------
                                  Number of             Proposed maximum            Proposed maximum           Amount of
     Title of securities          shares to              offering price            aggregate offering        registration
       to be registered       be registered (1)            per share                     price                    fee
- -----------------------------------------------------------------------------------------------------------------------------
<S>                           <C>                      <C>                        <C>                        <C>
   Common Stock, $.001 par        1,000,000                $13.90 (2)               $13,900,000 (2)             $1,279
       value per share
- -----------------------------------------------------------------------------------------------------------------------------
</TABLE>


(1)      In accordance with Rule 416 under the Securities Act of 1933, as
         amended (the "Securities Act"), this registration statement shall be
         deemed to cover any additional securities that may from time to time be
         offered or issued to prevent dilution resulting from stock splits,
         stock dividends or similar transactions.

(2)      Estimated solely for the purpose of calculating the registration fee,
         and based upon the average of the high and low sale prices of the
         Registrant's Common Stock on the Nasdaq National Market on January 24,
         2002 in accordance with Rules 457(c) and 457(h) of the Securities Act.

<PAGE>

PART I.           INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS

         Item 1.  Plan Information.
                  ----------------

         The information required by Item 1 is included in documents sent or
given to participants in the Amended and Restated 2000 Stock Incentive Plan of
OPNET Technologies, Inc. (the "Registrant"), pursuant to Rule 428(b)(1) under
the Securities Act of 1933, as amended (the "Securities Act").

         Item 2.  Registrant Information and Employee Plan Annual Information.
                  -----------------------------------------------------------

         The written statement required by Item 2 is included in documents sent
or given to participants in the Amended and Restated 2000 Stock Incentive Plan
of the Registrant pursuant to Rule 428(b)(1) under the Securities Act.

PART II.          INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

         Item 3.  Incorporation of Documents by Reference.
                  ---------------------------------------

         The Registrant is subject to the informational and reporting
requirements of Sections 13(a), 14 and 15(d) of the Securities Exchange Act of
1934, as amended (the "Exchange Act"), and in accordance therewith files
reports, proxy statements and other information with the Securities and Exchange
Commission (the "Commission"). The following documents, which are on file with
the Commission, are incorporated in this Registration Statement by reference:

           (a)    The Registrant's latest annual report filed pursuant to
Section 13(a) or 15(d) of the Exchange Act or the latest prospectus filed
pursuant to Rule 424(b) under the Securities Act that contains audited financial
statements for the Registrant's latest fiscal year for which such statements
have been filed.

           (b)    All other reports filed pursuant to Section 13(a) or 15(d) of
the Exchange Act since the end of the fiscal year covered by the document
referred to in (a) above.

           (c)    The description of the common stock of the Registrant, $.001
par value per share (the "Common Stock"), which is contained in the Registration
Statement on Form 8-A filed by the Registrant with the Commission on June 30,
2000, including any amendment or report filed for the purpose of updating such
description.

         All documents subsequently filed by the Registrant pursuant to Sections
13(a), 13(c), 14 and 15(d) of the Exchange Act, prior to the filing of a
post-effective amendment which indicates that all shares offered hereby have
been sold or which deregisters all shares then remaining unsold, shall be deemed
to be incorporated in this Registration Statement by reference and to be a part
hereof from the date of filing of such documents. Any statement contained in a
document incorporated or deemed to be incorporated by reference herein shall be
deemed to be modified or superseded for the purposes of this Registration
Statement to the extent a statement contained herein or in any other
subsequently filed document which also is or is deemed to be incorporated by
reference herein modifies or supersedes such statement. Any statement so
modified or superseded shall not be deemed, except as so modified or superseded,
to constitute a part of this Registration Statement.

         Item 4.  Description of Securities.
                  -------------------------

         Not applicable.

<PAGE>

         Item 5.  Interests of Named Experts and Counsel.
                  --------------------------------------

         Not applicable.

         Item 6.  Indemnification of Directors and Officers.
                  -----------------------------------------

         The Registrant's Third Amended and Restated Certificate of
Incorporation (the "Certificate") provides that, except to the extent prohibited
by the Delaware General Corporation Law (the "DGCL"), the Registrant's directors
shall not be personally liable to the Registrant or its stockholders for
monetary damages for any breach of fiduciary duty as directors of the
Registrant. Under the DGCL, the directors have a fiduciary duty to the
Registrant which is not eliminated by this provision of the Certificate and, in
appropriate circumstances, equitable remedies such as injunctive or other forms
of nonmonetary relief will remain available. In addition, each director will
continue to be subject to liability under the DGCL for breach of the director's
duty of loyalty to the Registrant, for acts or omissions which are found by a
court of competent jurisdiction to be not in good faith or involving intentional
misconduct, for knowing violations of law, for actions leading to improper
personal benefit to the director, and for payment of dividends or approval of
stock repurchases or redemptions that are prohibited by the DGCL. This provision
also does not affect the directors' responsibilities under any other laws, such
as the federal securities laws or state or federal environmental laws. The
Registrant has obtained liability insurance for its officers and directors.

         Section 145 of the DGCL empowers a corporation to indemnify its
directors and officers and to purchase insurance with respect to liability
arising out of their capacity or status as directors and officers, provided that
this provision shall not eliminate or limit the liability of a director: (i) for
any breach of the director's duty of loyalty to the corporation or its
stockholders, (ii) for acts or omissions not in good faith or which involve
intentional misconduct or a knowing violation of law, (iii) arising under
Section 174 of the DGCL including for an unlawful payment of dividend or
unlawful stock purchase or redemption or (iv) for any transaction from which the
director derived an improper personal benefit. The DGCL provides further that
the indemnification permitted thereunder shall not be deemed exclusive of any
other rights to which the directors and officers may be entitled under the
corporation's by-laws, any agreement, a vote of stockholders or otherwise. The
Certificate eliminates the personal liability of directors to the fullest extent
permitted by the DGCL and, together with the Registrant's Amended and Restated
By-Laws, provides that the Registrant shall fully indemnify any person who was
or is a party or is threatened to be made a party to any threatened, pending or
completed action, suit or proceeding (whether civil, criminal, administrative or
investigative) by reason of the fact that such person is or was a director or
officer of the Registrant, or is or was serving at the request of the Registrant
as a director or officer of another corporation, partnership, joint venture,
trust, employee benefit plan or other enterprise, against expenses (including
attorney's fees), judgments, fines and amounts paid in settlement actually and
reasonably incurred by such person in connection with such action, suit or
proceeding.

         Item 7.  Exemption from Registration Claimed.
                  -----------------------------------

         Not applicable.

         Item 8.  Exhibits.
                  --------

         The Exhibit Index immediately preceding the exhibits is attached hereto
and incorporated herein by reference.

<PAGE>

         Item 9.  Undertakings.
                  ------------

         1.       Item 512(a) of Regulation S-K.  The undersigned Registrant
                  -----------------------------
hereby undertakes:

           (a)    To file, during any period in which offers or sales are being
made, a post-effective amendment to this Registration Statement:

                  (i)    to include any prospectus required by Section 10(a)(3)
         of the Securities Act;

                  (ii)   to reflect in the prospectus any facts or events
         arising after the effective date of the Registration Statement (or the
         most recent post-effective amendment thereof) which, individually or in
         the aggregate, represent a fundamental change in the information set
         forth in the Registration Statement; and

                  (iii)  to include any material information with respect to the
         plan of distribution not previously disclosed in the Registration
         Statement or any material change to such information in the
         Registration Statement;

         provided, however, that paragraphs (i) and (ii) do not apply if the
         information required to be included in a post-effective amendment by
         those paragraphs is contained in periodic reports filed with or
         furnished to the Commission by the registrant pursuant to Section 13 or
         Section 15(d) of the Exchange Act that are incorporated by reference in
         the Registration Statement.

           (b)    That, for the purpose of determining any liability under the
Securities Act, each such post-effective amendment shall be deemed to be a new
registration statement relating to the securities offered therein, and the
offering of such securities at that time shall be deemed to be the initial bona
fide offering thereof.

           (c)    To remove from registration by means of a post-effective
amendment any of the securities being registered which remain unsold at the
termination of the offering.

         2.       Item 512(b) of Regulation S-K. The undersigned Registrant
                  -----------------------------
hereby undertakes that, for purposes of determining any liability under the
Securities Act, each filing of the Registrant's annual report pursuant to
Section 13(a) or Section 15(d) of the Exchange Act (and, where applicable, each
filing of an employee benefit plan's annual report pursuant to Section 15(d) of
the Exchange Act) that is incorporated by reference in the Registration
Statement shall be deemed to be a new registration statement relating to the
securities offered therein, and the offering of such securities at that time
shall be deemed to be the initial bona fide offering thereof.

         3.       Item 512(h) of Regulation S-K. Insofar as indemnification for
                  -----------------------------
liabilities arising under the Securities Act may be permitted to directors,
officers and controlling persons of the Registrant pursuant to the foregoing
provisions, or otherwise, the Registrant has been advised that in the opinion of
the Commission such indemnification is against public policy as expressed in the
Securities Act and is, therefore, unenforceable. In the event that a claim for
indemnification against such liabilities (other than the payment by the
Registrant of expenses incurred or paid by a director, officer or controlling
person of the Registrant in the successful defense of any action, suit or
proceeding) is asserted by such director, officer or controlling person in
connection with the securities being registered, the Registrant will, unless in
the opinion of its counsel the matter has been settled by controlling precedent,
submit to a court of appropriate jurisdiction the question whether such
indemnification by it is against public policy as expressed in the Securities
Act and will be governed by the final adjudication of such issue.

<PAGE>

                                   SIGNATURES

     Pursuant to the requirements of the Securities Act, the Registrant
certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing on Form S-8 and has duly caused this Registration
Statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in Bethesda, Maryland on January 25, 2002.

                                               OPNET TECHNOLOGIES, INC.



                                               By: /s/ Marc A. Cohen
                                                   -----------------------------
                                                   Marc A. Cohen
                                                   Chairman of the Board and
                                                   Chief Executive Officer


                                POWER OF ATTORNEY

     We, the undersigned officers and directors of OPNET Technologies, Inc.,
hereby severally constitute and appoint Marc A. Cohen, Alain J. Cohen, Dennis R.
McCoy and Brent B. Siler, and each of them singly, our true and lawful attorneys
with full power to them, and each of them singly, to sign for us and in our
names in the capacities indicated below, the Registration Statement on Form S-8
filed herewith and any and all subsequent amendments to said Registration
Statement, and generally to do all such things in our names and behalf in our
capacities as officers and directors to enable OPNET Technologies, Inc. to
comply with the provisions of the Securities Act of 1933, as amended, and all
requirements of the Securities and Exchange Commission, hereby ratifying and
confirming our signatures as they may be signed by said attorneys, or any of
them, to said Registration Statement and any and all amendments thereto.

     Pursuant to the requirements of the Securities Act, this Registration
Statement has been signed below by the following persons in the capacities and
on the dates indicated.

<TABLE>
<CAPTION>
Signature                           Title                                      Date
- ---------                           -----                                      ----
<S>                              <C>                                       <C>
/s/ Marc A. Cohen                Chairman of the Board and                 January 25, 2002
- ------------------------------   Chief Executive Officer
Marc A. Cohen                    (Principal Executive Officer)

/s/ Alain J. Cohen               President, Chief Technology Officer       January 25, 2002
- ------------------------------   and Director
Alain J. Cohen

/s/ Bruce R. Evans               Director                                  January 25, 2002
- ------------------------------
Bruce R. Evans

/s/ Steven G. Finn               Director                                  January 25, 2002
- ------------------------------
Steven G. Finn, PhD
</TABLE>


<PAGE>

<TABLE>
<S>                              <C>                                         <C>
/s/ Joseph W. Kuhn               Vice President of Finance and               January 25, 2002
- ------------------------------   Chief Financial Officer
Joseph W. Kuhn                   (Principal Financial and Accounting
                                 Officer)


/s/ William F. Stasior           Director                                    January 25, 2002
- ------------------------------
William F. Stasior
</TABLE>

<PAGE>

                                  EXHIBIT INDEX

<TABLE>
<CAPTION>
Exhibit
Number  Description
- ------  -----------
<S>     <C>
4.1*    Third Amended and Restated Certificate of Incorporation of the Registrant
4.2*    Amended and Restated Bylaws of the Registrant
5       Opinion of Hale and Dorr LLP, counsel to the Registrant
23.1    Consent of Deloitte & Touche LLP
23.2    Consent of Hale and Dorr LLP (included in Exhibit 5)
24      Power of Attorney (included on the signature page of this Registration
        Statement)
</TABLE>

* Incorporated by reference herein from Exhibits to the Registrant's
Registration Statement on Form S-1 (File No. 333-32588) as declared effective by
the Commission on August 1, 2000.
[{"type": "S-8", "sequence": "1", "filename": "ds8.txt", "description": "FORM S-8", "secsgml_size_bytes": 19132}]
{"company-data": {"conformed-name": "OPNET TECHNOLOGIES INC", "cik": "0001108924", "assigned-sic": "7373", "irs-number": "521483235", "state-of-incorporation": "DE", "fiscal-year-end": "0331"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-81504", "film-number": "02519410"}, "business-address": {"street1": "3400 INTERNATIONAL DRIVE N.W.", "city": "WASHINGTON", "state": "DC", "zip": "20008", "phone": "2023644700"}, "mail-address": {"street1": "3400 INTERNATIONAL DRIVE, N.W.", "city": "WASHINGTON", "state": "DC", "zip": "20008"}}
As filed with the Securities and Exchange Commission on January 28, 2002
                                                     Registration No. 333-_____
- --------------------------------------------------------------------------------

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D. C. 20549

                                 ______________

                                    Form S-8
                          REGISTRATION STATEMENT UNDER
                           THE SECURITIES ACT OF 1933

                               ___________________

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

                               ___________________
              Delaware                                          52-1483235
   (State or other jurisdiction of                           (I.R.S. Employer
   incorporation or organization)                         Identification Number)

                          ____________________________

                              7255 Woodmont Avenue
                            Bethesda, Maryland 20814
                                 (240) 497-3000
       (Address, including zip code, and telephone number, including area
               code, of registrant's principal executive offices)

                 AMENDED AND RESTATED 2000 STOCK INCENTIVE PLAN
                            (Full title of the Plan)

                                  Marc A. Cohen
                Chairman of the Board and Chief Executive Officer
                            OPNET TECHNOLOGIES, INC.
                              7255 Woodmont Avenue
                            Bethesda, Maryland 20814
                                 (240) 497-3000
     (Name and address, including zip code, and telephone number, including
                        area code, of agent for service)

                         CALCULATION OF REGISTRATION FEE
- -----------------------------------------------------------------------------------------------------------------------------
                                  Number of             Proposed maximum            Proposed maximum           Amount of
     Title of securities          shares to              offering price            aggregate offering        registration
       to be registered       be registered (1)            per share                     price                    fee
- -----------------------------------------------------------------------------------------------------------------------------
Common Stock, $.001 par        1,000,000                $13.90 (2)               $13,900,000 (2)             $1,279
       value per share
- -----------------------------------------------------------------------------------------------------------------------------
(1)      In accordance with Rule 416 under the Securities Act of 1933, as
         amended (the "Securities Act"), this registration statement shall be
         deemed to cover any additional securities that may from time to time be
         offered or issued to prevent dilution resulting from stock splits,
         stock dividends or similar transactions.

(2)      Estimated solely for the purpose of calculating the registration fee,
         and based upon the average of the high and low sale prices of the
         Registrant's Common Stock on the Nasdaq National Market on January 24,
         2002 in accordance with Rules 457(c) and 457(h) of the Securities Act.
PART I.           INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS

         Item 1.  Plan Information.
                  ----------------

         The information required by Item 1 is included in documents sent or
given to participants in the Amended and Restated 2000 Stock Incentive Plan of
OPNET Technologies, Inc. (the "Registrant"), pursuant to Rule 428(b)(1) under
the Securities Act of 1933, as amended (the "Securities Act").

         Item 2.  Registrant Information and Employee Plan Annual Information.
                  -----------------------------------------------------------

         The written statement required by Item 2 is included in documents sent
or given to participants in the Amended and Restated 2000 Stock Incentive Plan
of the Registrant pursuant to Rule 428(b)(1) under the Securities Act.

PART II.          INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

         Item 3.  Incorporation of Documents by Reference.
                  ---------------------------------------

         The Registrant is subject to the informational and reporting
requirements of Sections 13(a), 14 and 15(d) of the Securities Exchange Act of
1934, as amended (the "Exchange Act"), and in accordance therewith files
reports, proxy statements and other information with the Securities and Exchange
Commission (the "Commission"). The following documents, which are on file with
the Commission, are incorporated in this Registration Statement by reference:

           (a)    The Registrant's latest annual report filed pursuant to
Section 13(a) or 15(d) of the Exchange Act or the latest prospectus filed
pursuant to Rule 424(b) under the Securities Act that contains audited financial
statements for the Registrant's latest fiscal year for which such statements
have been filed.

           (b)    All other reports filed pursuant to Section 13(a) or 15(d) of
the Exchange Act since the end of the fiscal year covered by the document
referred to in (a) above.

           (c)    The description of the common stock of the Registrant, $.001
par value per share (the "Common Stock"), which is contained in the Registration
Statement on Form 8-A filed by the Registrant with the Commission on June 30,
2000, including any amendment or report filed for the purpose of updating such
description.

         All documents subsequently filed by the Registrant pursuant to Sections
13(a), 13(c), 14 and 15(d) of the Exchange Act, prior to the filing of a
post-effective amendment which indicates that all shares offered hereby have
been sold or which deregisters all shares then remaining unsold, shall be deemed
to be incorporated in this Registration Statement by reference and to be a part
hereof from the date of filing of such documents. Any statement contained in a
document incorporated or deemed to be incorporated by reference herein shall be
deemed to be modified or superseded for the purposes of this Registration
Statement to the extent a statement contained herein or in any other
subsequently filed document which also is or is deemed to be incorporated by
reference herein modifies or supersedes such statement. Any statement so
modified or superseded shall not be deemed, except as so modified or superseded,
to constitute a part of this Registration Statement.

         Item 4.  Description of Securities.
                  -------------------------

         Not applicable.
Item 5.  Interests of Named Experts and Counsel.
                  --------------------------------------

         Not applicable.

         Item 6.  Indemnification of Directors and Officers.
                  -----------------------------------------

         The Registrant's Third Amended and Restated Certificate of
Incorporation (the "Certificate") provides that, except to the extent prohibited
by the Delaware General Corporation Law (the "DGCL"), the Registrant's directors
shall not be personally liable to the Registrant or its stockholders for
monetary damages for any breach of fiduciary duty as directors of the
Registrant. Under the DGCL, the directors have a fiduciary duty to the
Registrant which is not eliminated by this provision of the Certificate and, in
appropriate circumstances, equitable remedies such as injunctive or other forms
of nonmonetary relief will remain available. In addition, each director will
continue to be subject to liability under the DGCL for breach of the director's
duty of loyalty to the Registrant, for acts or omissions which are found by a
court of competent jurisdiction to be not in good faith or involving intentional
misconduct, for knowing violations of law, for actions leading to improper
personal benefit to the director, and for payment of dividends or approval of
stock repurchases or redemptions that are prohibited by the DGCL. This provision
also does not affect the directors' responsibilities under any other laws, such
as the federal securities laws or state or federal environmental laws. The
Registrant has obtained liability insurance for its officers and directors.

         Section 145 of the DGCL empowers a corporation to indemnify its
directors and officers and to purchase insurance with respect to liability
arising out of their capacity or status as directors and officers, provided that
this provision shall not eliminate or limit the liability of a director: (i) for
any breach of the director's duty of loyalty to the corporation or its
stockholders, (ii) for acts or omissions not in good faith or which involve
intentional misconduct or a knowing violation of law, (iii) arising under
Section 174 of the DGCL including for an unlawful payment of dividend or
unlawful stock purchase or redemption or (iv) for any transaction from which the
director derived an improper personal benefit. The DGCL provides further that
the indemnification permitted thereunder shall not be deemed exclusive of any
other rights to which the directors and officers may be entitled under the
corporation's by-laws, any agreement, a vote of stockholders or otherwise. The
Certificate eliminates the personal liability of directors to the fullest extent
permitted by the DGCL and, together with the Registrant's Amended and Restated
By-Laws, provides that the Registrant shall fully indemnify any person who was
or is a party or is threatened to be made a party to any threatened, pending or
completed action, suit or proceeding (whether civil, criminal, administrative or
investigative) by reason of the fact that such person is or was a director or
officer of the Registrant, or is or was serving at the request of the Registrant
as a director or officer of another corporation, partnership, joint venture,
trust, employee benefit plan or other enterprise, against expenses (including
attorney's fees), judgments, fines and amounts paid in settlement actually and
reasonably incurred by such person in connection with such action, suit or
proceeding.

         Item 7.  Exemption from Registration Claimed.
                  -----------------------------------

         Not applicable.

         Item 8.  Exhibits.
                  --------

         The Exhibit Index immediately preceding the exhibits is attached hereto
and incorporated herein by reference.
Item 9.  Undertakings.
                  ------------

         1.       Item 512(a) of Regulation S-K.  The undersigned Registrant
                  -----------------------------
hereby undertakes:

           (a)    To file, during any period in which offers or sales are being
made, a post-effective amendment to this Registration Statement:

                  (i)    to include any prospectus required by Section 10(a)(3)
         of the Securities Act;

                  (ii)   to reflect in the prospectus any facts or events
         arising after the effective date of the Registration Statement (or the
         most recent post-effective amendment thereof) which, individually or in
         the aggregate, represent a fundamental change in the information set
         forth in the Registration Statement; and

                  (iii)  to include any material information with respect to the
         plan of distribution not previously disclosed in the Registration
         Statement or any material change to such information in the
         Registration Statement;

         provided, however, that paragraphs (i) and (ii) do not apply if the
         information required to be included in a post-effective amendment by
         those paragraphs is contained in periodic reports filed with or
         furnished to the Commission by the registrant pursuant to Section 13 or
         Section 15(d) of the Exchange Act that are incorporated by reference in
         the Registration Statement.

           (b)    That, for the purpose of determining any liability under the
Securities Act, each such post-effective amendment shall be deemed to be a new
registration statement relating to the securities offered therein, and the
offering of such securities at that time shall be deemed to be the initial bona
fide offering thereof.

           (c)    To remove from registration by means of a post-effective
amendment any of the securities being registered which remain unsold at the
termination of the offering.

         2.       Item 512(b) of Regulation S-K. The undersigned Registrant
                  -----------------------------
hereby undertakes that, for purposes of determining any liability under the
Securities Act, each filing of the Registrant's annual report pursuant to
Section 13(a) or Section 15(d) of the Exchange Act (and, where applicable, each
filing of an employee benefit plan's annual report pursuant to Section 15(d) of
the Exchange Act) that is incorporated by reference in the Registration
Statement shall be deemed to be a new registration statement relating to the
securities offered therein, and the offering of such securities at that time
shall be deemed to be the initial bona fide offering thereof.

         3.       Item 512(h) of Regulation S-K. Insofar as indemnification for
                  -----------------------------
liabilities arising under the Securities Act may be permitted to directors,
officers and controlling persons of the Registrant pursuant to the foregoing
provisions, or otherwise, the Registrant has been advised that in the opinion of
the Commission such indemnification is against public policy as expressed in the
Securities Act and is, therefore, unenforceable. In the event that a claim for
indemnification against such liabilities (other than the payment by the
Registrant of expenses incurred or paid by a director, officer or controlling
person of the Registrant in the successful defense of any action, suit or
proceeding) is asserted by such director, officer or controlling person in
connection with the securities being registered, the Registrant will, unless in
the opinion of its counsel the matter has been settled by controlling precedent,
submit to a court of appropriate jurisdiction the question whether such
indemnification by it is against public policy as expressed in the Securities
Act and will be governed by the final adjudication of such issue.
SIGNATURES

     Pursuant to the requirements of the Securities Act, the Registrant
certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing on Form S-8 and has duly caused this Registration
Statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in Bethesda, Maryland on January 25, 2002.

                                               OPNET TECHNOLOGIES, INC.

                                               By: /s/ Marc A. Cohen
                                                   -----------------------------
                                                   Marc A. Cohen
                                                   Chairman of the Board and
                                                   Chief Executive Officer

                                POWER OF ATTORNEY

     We, the undersigned officers and directors of OPNET Technologies, Inc.,
hereby severally constitute and appoint Marc A. Cohen, Alain J. Cohen, Dennis R.
McCoy and Brent B. Siler, and each of them singly, our true and lawful attorneys
with full power to them, and each of them singly, to sign for us and in our
names in the capacities indicated below, the Registration Statement on Form S-8
filed herewith and any and all subsequent amendments to said Registration
Statement, and generally to do all such things in our names and behalf in our
capacities as officers and directors to enable OPNET Technologies, Inc. to
comply with the provisions of the Securities Act of 1933, as amended, and all
requirements of the Securities and Exchange Commission, hereby ratifying and
confirming our signatures as they may be signed by said attorneys, or any of
them, to said Registration Statement and any and all amendments thereto.

     Pursuant to the requirements of the Securities Act, this Registration
Statement has been signed below by the following persons in the capacities and
on the dates indicated.
Signature                           Title                                      Date
- ---------                           -----                                      ----
/s/ Marc A. Cohen                Chairman of the Board and                 January 25, 2002
- ------------------------------   Chief Executive Officer
Marc A. Cohen                    (Principal Executive Officer)

/s/ Alain J. Cohen               President, Chief Technology Officer       January 25, 2002
- ------------------------------   and Director
Alain J. Cohen

/s/ Bruce R. Evans               Director                                  January 25, 2002
- ------------------------------
Bruce R. Evans

/s/ Steven G. Finn               Director                                  January 25, 2002
- ------------------------------
Steven G. Finn, PhD
/s/ Joseph W. Kuhn               Vice President of Finance and               January 25, 2002
- ------------------------------   Chief Financial Officer
Joseph W. Kuhn                   (Principal Financial and Accounting
                                 Officer)

/s/ William F. Stasior           Director                                    January 25, 2002
- ------------------------------
William F. Stasior
EXHIBIT INDEX
Exhibit
Number  Description
- ------  -----------
4.1*    Third Amended and Restated Certificate of Incorporation of the Registrant
4.2*    Amended and Restated Bylaws of the Registrant
5       Opinion of Hale and Dorr LLP, counsel to the Registrant
23.1    Consent of Deloitte & Touche LLP
23.2    Consent of Hale and Dorr LLP (included in Exhibit 5)
24      Power of Attorney (included on the signature page of this Registration
        Statement)
* Incorporated by reference herein from Exhibits to the Registrant's
Registration Statement on Form S-1 (File No. 333-32588) as declared effective by
the Commission on August 1, 2000.