<PAGE>   1

      As filed with the Securities and Exchange Commission on June 8, 2001
                                                    Registration No. 333-_______

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

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

                         INTERNET SECURITY SYSTEMS, INC.
             (Exact name of registrant as specified in its charter)

               DELAWARE                                         58-2362189
     (State or other jurisdiction                              (IRS Employer
   of incorporation or organization)                        Identification No.)

                               6303 BARFIELD ROAD
                             ATLANTA, GEORGIA 30328
          (Address of principal executive offices, including zip code)

                       1999 NETWORK ICE STOCK OPTION PLAN

                       RESTATED 1995 STOCK INCENTIVE PLAN
                 (as Amended and Restated through May 23, 2001)
                            (Full title of the plans)

                                THOMAS E. NOONAN
                 CHAIRMAN, PRESIDENT AND CHIEF EXECUTIVE OFFICER
                         INTERNET SECURITY SYSTEMS, INC.
                               6303 BARFIELD ROAD
                             ATLANTA, GEORGIA 30328
                     (Name and address of agent for service)

                                 (404) 236-2600
          (Telephone number, including area code, of agent for service)

                         CALCULATION OF REGISTRATION FEE

<TABLE>
<CAPTION>
============================================================================================================================
                                                               PROPOSED MAXIMUM     PROPOSED MAXIMUM
                                            AMOUNT TO BE      OFFERING PRICE PER   AGGREGATE OFFERING       AMOUNT OF
TITLE OF SECURITIES TO BE REGISTERED        REGISTERED(1)            SHARE                PRICE          REGISTRATION FEE
----------------------------------------------------------------------------------------------------------------------------
<S>                                        <C>                <C>                  <C>                   <C>
1999 Network ICE Stock  Option Plan
Common Stock, $0.001 par value               289,205 shares       $47.15 (2)       $ 13,636,016 (2)         $ 3,410
----------------------------------------------------------------------------------------------------------------------------

Restated 1995 Stock  Incentive Plan
Common Stock, $0.001 par value             3,000,000 shares       $47.15 (2)       $141,450,000 (2)         $35,362
----------------------------------------------------------------------------------------------------------------------------

Aggregate Registration Fee                 3,289,205 shares       $47.15 (2)       $155,086,016 (2)         $38,772
============================================================================================================================
</TABLE>


<PAGE>   2



(1)      This Registration Statement shall also cover any additional shares of
Common Stock that become issuable under the 1999 Network ICE Stock Option Plan
and the Restated 1995 Stock Incentive Plan by reason of any stock dividend,
stock split, recapitalization or other similar transaction effected without the
Company's receipt of consideration that results in an increase in the number of
outstanding shares of the Company's Common Stock.

(2)      Calculated solely for purposes of this offering under Rule 457(h) of
the Securities Act of 1933, as amended, on the basis of the average of the high
and low selling prices per share of the Company's Common Stock on June 4, 2001,
as reported by the Nasdaq National Market.


<PAGE>   3


                                     PART I

              INFORMATION REQUIRED IN THE SECTION 10(A) PROSPECTUS

         The documents containing the information specified in Part I will be
sent or given to option plan participants of Internet Security Systems, Inc.
(the "Company") as specified by Rule 428(b)(1) of the Securities Act of 1933, as
amended (the "Securities Act"). In accordance with the instructions of Part I of
Form S-8, such documents will not be filed with the Securities and Exchange
Commission (the "Commission") either as part of this Registration Statement or
as prospectuses or prospectus supplements pursuant to Rule 424 of the Securities
Act. These documents and the documents incorporated by reference pursuant to
Item 3 of Part II of this Registration Statement, taken together, constitute a
prospectus as required by Section 10(a) of the Securities Act.


                                     PART II

         This Registration Statement on Form S-8 relates to (i) 289,205 shares
of common stock, par value $0.001 per share (the "Common Stock"), of the Company
to be issued pursuant to the 1999 Network ICE Stock Option Plan and (ii) an
additional 3,000,000 shares of Common Stock to be issued pursuant to the
Company's Restated 1995 Stock Incentive Plan.


               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3.     INCORPORATION OF DOCUMENTS BY REFERENCE

         The Company hereby incorporates by reference into this Registration
Statement the following documents previously filed with the Commission:

         (a)      The Company's Annual Report on Form 10-K filed with the
Commission on March 30, 2001 for the fiscal year ended December 31, 2000;

         (b)      The Company's Quarterly Report on Form 10-Q filed with the
Commission on May 11, 2001 for the fiscal period ended March 31, 2001;

         (c)      The Company's Current Report on Form 8-K filed with the
Commission on June 8, 2001; and

         (d)      The  Company's Registration Statement No. 000-23655 on
Form 8-A filed with the Commission on March 13, 1998, in which the terms, rights
and provisions applicable to the Company's outstanding Common Stock are
described.

         All documents filed by the Company pursuant to Section 13(a), 13(c), 14
or 15(d) of the Securities Exchange Act of 1934, as amended (the "Exchange Act")
after the date of this Registration Statement and prior to the filing of a
post-effective amendment which indicates that all securities offered hereby have
been sold or which deregisters all securities then remaining unsold, shall be
deemed to be


<PAGE>   4
incorporated by reference into this Registration Statement 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 purposes of this Registration Statement
to the extent that a statement contained herein or in any subsequently filed
document which also is deemed to be incorporated by reference herein modifies or
supersedes such statement. Any such 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

         King & Spalding is legal counsel to the Company and is giving an
opinion upon the validity of the Common Stock being registered pursuant to this
Registration Statement. Sam Nunn, a partner at King & Spalding, serves on the
Company's board of directors.

ITEM 6.           INDEMNIFICATION OF DIRECTORS AND OFFICERS

         Subsection (a) of Section 145 of the Delaware General Corporation Law
empowers a corporation to 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
(other than an action by or in the right of the corporation) by reason of the
fact that the person is or was a director, officer, employee or agent of the
corporation, or is or was serving at the request of the corporation as a
director, officer, employee or agent of another corporation, partnership, joint
venture, trust or other enterprise, against expenses (including attorneys'
fees), judgments, fines and amounts paid in settlement actually and reasonably
incurred by the person in connection with such action, suit or proceeding if the
person acted in good faith and in a manner the person reasonably believed to be
in or not opposed to the best interests of the corporation, and, with respect to
any criminal action or proceeding, had no reasonable cause to believe the
person's conduct was unlawful.

         Subsection (b) of Section 145 empowers a corporation to indemnify any
person who was or is a party or is threatened to be made a party to any
threatened, pending or completed action or suit by or in the right of the
corporation to procure a judgment in its favor by reason of the fact that the
person acted in any of the capacities set forth above, against expenses
(including attorneys' fees) actually and reasonably incurred by the person in
connection with the defense or settlement of such action or suit if the person
acted in good faith and in a manner the person reasonably believed to be in or
not opposed to the best interests of the corporation, except that no
indemnification may be made in respect to any claim, issue or matter as to which
such person shall have been adjudged to be liable to the corporation unless and
only to the extent that the Court of Chancery or the court in which such action
or suit was brought shall determine upon application that, despite the
adjudication of liability but in view of all the circumstances of the case, such
person is fairly and reasonably entitled to indemnity for such expenses which
the Court of Chancery or such other court shall deem proper.


                                      II-2
<PAGE>   5

         Section 145 further provides that to the extent a present or former
director or officer of a corporation has been successful on the merits or
otherwise in the defense of any such action, suit or proceeding referred to in
subsections (a) and (b) of Section 145, or in the defense of any claim, issue or
matter therein, such person shall be indemnified against expenses (including
attorneys' fees) actually and reasonably incurred by such person in connection
therewith; that the indemnification provided for by Section 145 shall not be
deemed exclusive of any other rights which the indemnified party may be
entitled; that indemnification provided by Section 145 shall, unless otherwise
provided when authorized or ratified, continue as to a person who has ceased to
be a director, officer, employee or agent and shall inure to the benefit of such
person's heirs, executors and administrators; and empowers the corporation to
purchase and maintain insurance on behalf of any person who is or was serving at
the request of the corporation as a director, officer, employee or agent of
another corporation, partnership, joint venture, trust or other enterprise
against any liability asserted against such person and incurred by such person
in any such capacity, or arising out of such person's status as such, whether or
not the corporation would have the power to indemnify such person against such
liabilities under Section 145.

         Section 102(b)(7) of the Delaware General Corporation Law provides that
a certificate of incorporation may contain a provision eliminating or limiting
the personal liability of a director to the corporation or its stockholders for
monetary damages for breach of fiduciary duty as a director, provided that such
provision shall not eliminate or limit the liability of the director for (i) any
breach of the director's duty of loyalty to the corporation or its stockholders,
(ii) acts or omissions not in good faith or which involve intentional misconduct
or a knowing violation of law, (iii) the payment of unlawful dividends or
unlawful purchases or redemption of the corporation's stock or (iv) any
transaction from which the director derived an improper personal benefit.

         Article V of the Company's Restated Certificate of Incorporation
provides that, to the fullest extent permitted by the Delaware General
Corporation Law as the same exists or as it may hereafter be amended, no
director of the Company shall be personally liable to the Company or its
stockholders for monetary damages for breach of fiduciary duty as a director.

         Article XI of the Company's bylaws further provides that the Company
shall, to the fullest extent not prohibited by the Delaware General Corporation
Law, indemnify each of its directors and executive officers, subject to
limitations, if any, set forth in individual contracts with such directors and
executive officers and limitations on proceedings, or parts thereof, initiated
by such directors or executive officers. The Company has the power to indemnify
its other officers, employees and other agents as permitted by Delaware General
Corporation Law. The Company has entered into indemnification agreements with
each of its directors and executive officers that provide for indemnification
and expense advancement to the fullest extent permitted under the Delaware
General Corporation Law.

         The Company has purchased officers' and directors' liability insurance.

ITEM 7.           EXEMPTION FROM REGISTRATION CLAIMED

         Not Applicable.


                                      II-3
<PAGE>   6

ITEM 8.           EXHIBITS

<TABLE>
<CAPTION>

         Exhibit
         -------

         <S>              <C>
         3.1              Restated Certificate of Incorporation (filed as Exhibit 3.1 to the Company's
                          Quarterly Report on Form 10-Q, dated November 14, 2000).

         3.2              Bylaws (filed as Exhibit 3.2 to the Company's Registration
                          Statement on Form S-1, Registration No. 333-44529).

         4.1              1999 Network ICE Stock Option Plan.

         4.2              1995 Stock Incentive Plan (as amended and restated as of May 23, 2001).

         4.3              See Exhibits 3.1, 3.2 and the Company's Registration Statement on
                          Form 8-A, Registration No. 000-23655, together with any exhibits thereto,
                          defining the rights of holders of the Company's Common Stock.

         5.1              Opinion and consent of King & Spalding.

        23.1              Consent of Ernst & Young LLP.

        23.2              Consent of PricewaterhouseCoopers LLP., Independent Accountants

        23.3              Consent of PricewaterhouseCoopers LLP., Independent Accountants

        23.4              Consent of King & Spalding (included in Exhibit 5.1).

        24.1              Power of Attorney (included on the signature page).
</TABLE>

ITEM 9.           UNDERTAKINGS

         (a)      The undersigned registrant hereby undertakes:

                  (1)      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 this 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 this
Registration Statement.


                                      II-4
<PAGE>   7
                           (iii) To include any material information with
respect to the plan of distribution not previously disclosed in this
Registration Statement or any material change to such information in this
Registration Statement;

provided, however, that clauses (a)(1)(i) and (a)(1)(ii) do not apply if the
information required to be included in a post-effective amendment by those
clauses 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 into this Registration
Statement.

                  (2) 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.

                  (3) 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 1999 Network ICE Stock Option Plan and the Company's Restated
1995 Stock Incentive Plan.

         (b) 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 that is incorporated by reference into this 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.

         (c) Insofar as indemnification for liabilities arising under the
Securities Act may be permitted to directors, officers or 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.

                                      II-5
<PAGE>   8


                                   SIGNATURES

         Pursuant to the requirements of the Securities Act, the Company
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 the City of Atlanta, State of Georgia on this 8th day of June,
2001.



                                INTERNET SECURITY SYSTEMS, INC.


                                By: /s/ Thomas E. Noonan
                                   ---------------------------------------------
                                   Thomas E. Noonan
                                   Chairman, President and
                                   Chief Executive Officer


                                POWER OF ATTORNEY


         KNOW ALL PERSONS BY THESE PRESENTS that each of the persons whose
signature appears below, does hereby constitute and appoint Thomas E. Noonan and
Richard Macchia and each of them, the lawful attorneys-in-fact and agents with
full power and authority to do any and all acts and things and to execute any
and all instruments which said attorneys and agents, and any one of them,
determine may be necessary or advisable or required to enable the Company to
comply with the Securities Act, and any rules or regulations or requirements of
the Commission in connection with this Registration Statement on Form S-8.
Without limiting the generality of the foregoing power and authority, the powers
granted include the power and authority to sign the names of the undersigned
officers and directors in the capacities indicated below to this Registration
Statement, to any and all amendments, both pre-effective and post-effective, and
supplements to this Registration Statement, and to any and all instruments or
documents filed as part of or in conjunction with this Registration Statement or
amendments or supplements thereof, and each of the undersigned hereby ratifies
and confirms all that said attorneys and agents, or any one of them, shall do or
cause to be done by virtue hereof. This Power of Attorney may be signed in
several counterparts.


                                      II-6
<PAGE>   9


         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/ Thomas E. Noonan                                  Chairman, President and Chief Executive Officer   June 8, 2001
--------------------------------------------          (Principal Executive Officer)
Thomas E. Noonan

/s/ Christopher W. Klaus                              Chief Technology Officer and Director             June 8, 2001
--------------------------------------------
Christopher W. Klaus

/s/ Richard Macchia                                   Vice President and Chief Financial                June 8, 2001
--------------------------------------------          Officer (Principal Financial
Richard Macchia                                       Officer)

/s/ Maureen Richards                                  Controller (Principal Accounting Officer)         June 8, 2001
--------------------------------------------
Maureen Richards

/s/ Richard S. Bodman                                 Director                                          June 8, 2001
--------------------------------------------
Richard S. Bodman

/s/ Robert E. Davoli                                  Director                                          June 8, 2001
--------------------------------------------
Robert E. Davoli

/s/ Kevin E. O'Connor                                 Director                                          June 8, 2001
--------------------------------------------
Kevin J. O'Connor

/s/ Sam Nunn                                          Director                                          June 8, 2001
--------------------------------------------
Sam Nunn

                                                      Director
--------------------------------------------
David N. Strohm
</TABLE>


                                      II-7
<PAGE>   10



                                  EXHIBIT INDEX

<TABLE>
<CAPTION>
         Exhibit
         -------
         <S>              <C>
         3.1              Restated Certificate of Incorporation (filed as Exhibit 3.1 to the Company's
                          Quarterly Report on Form 10-Q, dated November 14, 2000).

         3.2              Bylaws (filed as Exhibit 3.2 to the Company's Registration Statement on
                          Form S-1, Registration No. 333-44529).

         4.1              1999 Network ICE Stock Option Plan.

         4.2              1995 Stock Incentive Plan (as amended and restated through May 23, 2001).

         4.3              See Exhibits 3.1, 3.2 and the Company's Registration Statement on Form 8-A,
                          Registration No. 000-23655, together with any exhibits thereto, defining the rights
                          of holders of the Company's Common Stock.

         5.1              Opinion of King & Spalding.

        23.1              Consent of Ernst & Young LLP.

        23.2              Consent of PriceWaterhouseCoopers LLP., Independent Accountants

        23.3              Consent of PricewaterhouseCoopers LLP., Independent Accountants

        23.4              Consent of King & Spalding (included in Exhibit 5.1).

        24.1              Power of Attorney (included on the signature page).
</TABLE>



                                     II-8
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{"company-data": {"conformed-name": "INTERNET SECURITY SYSTEMS INC/GA", "cik": "0001053148", "assigned-sic": "7372", "irs-number": "582362189", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-62658", "film-number": "1657684"}, "business-address": {"street1": "6303 BARFIELD ROAD", "street2": ".", "city": "ATLANTA", "state": "GA", "zip": "30328", "phone": "404-236-2600"}, "mail-address": {"street1": "6303 BARFIELD ROAD", "street2": ".", "city": "ATLANTA", "state": "GA", "zip": "30328"}, "former-company": {"former-conformed-name": "ISS GROUP INC", "date-changed": "19980116"}}
1

      As filed with the Securities and Exchange Commission on June 8, 2001
                                                    Registration No. 333-_______

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

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

                         INTERNET SECURITY SYSTEMS, INC.
             (Exact name of registrant as specified in its charter)

               DELAWARE                                         58-2362189
     (State or other jurisdiction                              (IRS Employer
   of incorporation or organization)                        Identification No.)

                               6303 BARFIELD ROAD
                             ATLANTA, GEORGIA 30328
          (Address of principal executive offices, including zip code)

                       1999 NETWORK ICE STOCK OPTION PLAN

                       RESTATED 1995 STOCK INCENTIVE PLAN
                 (as Amended and Restated through May 23, 2001)
                            (Full title of the plans)

                                THOMAS E. NOONAN
                 CHAIRMAN, PRESIDENT AND CHIEF EXECUTIVE OFFICER
                         INTERNET SECURITY SYSTEMS, INC.
                               6303 BARFIELD ROAD
                             ATLANTA, GEORGIA 30328
                     (Name and address of agent for service)

                                 (404) 236-2600
          (Telephone number, including area code, of agent for service)

                         CALCULATION OF REGISTRATION FEE
============================================================================================================================
                                                               PROPOSED MAXIMUM     PROPOSED MAXIMUM
                                            AMOUNT TO BE      OFFERING PRICE PER   AGGREGATE OFFERING       AMOUNT OF
TITLE OF SECURITIES TO BE REGISTERED        REGISTERED(1)            SHARE                PRICE          REGISTRATION FEE
----------------------------------------------------------------------------------------------------------------------------
1999 Network ICE Stock  Option Plan
Common Stock, $0.001 par value               289,205 shares       $47.15 (2)       $ 13,636,016 (2)         $ 3,410
----------------------------------------------------------------------------------------------------------------------------

Restated 1995 Stock  Incentive Plan
Common Stock, $0.001 par value             3,000,000 shares       $47.15 (2)       $141,450,000 (2)         $35,362
----------------------------------------------------------------------------------------------------------------------------

Aggregate Registration Fee                 3,289,205 shares       $47.15 (2)       $155,086,016 (2)         $38,772
============================================================================================================================
2

(1)      This Registration Statement shall also cover any additional shares of
Common Stock that become issuable under the 1999 Network ICE Stock Option Plan
and the Restated 1995 Stock Incentive Plan by reason of any stock dividend,
stock split, recapitalization or other similar transaction effected without the
Company's receipt of consideration that results in an increase in the number of
outstanding shares of the Company's Common Stock.

(2)      Calculated solely for purposes of this offering under Rule 457(h) of
the Securities Act of 1933, as amended, on the basis of the average of the high
and low selling prices per share of the Company's Common Stock on June 4, 2001,
as reported by the Nasdaq National Market.
3

                                     PART I

              INFORMATION REQUIRED IN THE SECTION 10(A) PROSPECTUS

         The documents containing the information specified in Part I will be
sent or given to option plan participants of Internet Security Systems, Inc.
(the "Company") as specified by Rule 428(b)(1) of the Securities Act of 1933, as
amended (the "Securities Act"). In accordance with the instructions of Part I of
Form S-8, such documents will not be filed with the Securities and Exchange
Commission (the "Commission") either as part of this Registration Statement or
as prospectuses or prospectus supplements pursuant to Rule 424 of the Securities
Act. These documents and the documents incorporated by reference pursuant to
Item 3 of Part II of this Registration Statement, taken together, constitute a
prospectus as required by Section 10(a) of the Securities Act.

                                     PART II

         This Registration Statement on Form S-8 relates to (i) 289,205 shares
of common stock, par value $0.001 per share (the "Common Stock"), of the Company
to be issued pursuant to the 1999 Network ICE Stock Option Plan and (ii) an
additional 3,000,000 shares of Common Stock to be issued pursuant to the
Company's Restated 1995 Stock Incentive Plan.

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3.     INCORPORATION OF DOCUMENTS BY REFERENCE

         The Company hereby incorporates by reference into this Registration
Statement the following documents previously filed with the Commission:

         (a)      The Company's Annual Report on Form 10-K filed with the
Commission on March 30, 2001 for the fiscal year ended December 31, 2000;

         (b)      The Company's Quarterly Report on Form 10-Q filed with the
Commission on May 11, 2001 for the fiscal period ended March 31, 2001;

         (c)      The Company's Current Report on Form 8-K filed with the
Commission on June 8, 2001; and

         (d)      The  Company's Registration Statement No. 000-23655 on
Form 8-A filed with the Commission on March 13, 1998, in which the terms, rights
and provisions applicable to the Company's outstanding Common Stock are
described.

         All documents filed by the Company pursuant to Section 13(a), 13(c), 14
or 15(d) of the Securities Exchange Act of 1934, as amended (the "Exchange Act")
after the date of this Registration Statement and prior to the filing of a
post-effective amendment which indicates that all securities offered hereby have
been sold or which deregisters all securities then remaining unsold, shall be
deemed to be
4
incorporated by reference into this Registration Statement 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 purposes of this Registration Statement
to the extent that a statement contained herein or in any subsequently filed
document which also is deemed to be incorporated by reference herein modifies or
supersedes such statement. Any such 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

         King & Spalding is legal counsel to the Company and is giving an
opinion upon the validity of the Common Stock being registered pursuant to this
Registration Statement. Sam Nunn, a partner at King & Spalding, serves on the
Company's board of directors.

ITEM 6.           INDEMNIFICATION OF DIRECTORS AND OFFICERS

         Subsection (a) of Section 145 of the Delaware General Corporation Law
empowers a corporation to 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
(other than an action by or in the right of the corporation) by reason of the
fact that the person is or was a director, officer, employee or agent of the
corporation, or is or was serving at the request of the corporation as a
director, officer, employee or agent of another corporation, partnership, joint
venture, trust or other enterprise, against expenses (including attorneys'
fees), judgments, fines and amounts paid in settlement actually and reasonably
incurred by the person in connection with such action, suit or proceeding if the
person acted in good faith and in a manner the person reasonably believed to be
in or not opposed to the best interests of the corporation, and, with respect to
any criminal action or proceeding, had no reasonable cause to believe the
person's conduct was unlawful.

         Subsection (b) of Section 145 empowers a corporation to indemnify any
person who was or is a party or is threatened to be made a party to any
threatened, pending or completed action or suit by or in the right of the
corporation to procure a judgment in its favor by reason of the fact that the
person acted in any of the capacities set forth above, against expenses
(including attorneys' fees) actually and reasonably incurred by the person in
connection with the defense or settlement of such action or suit if the person
acted in good faith and in a manner the person reasonably believed to be in or
not opposed to the best interests of the corporation, except that no
indemnification may be made in respect to any claim, issue or matter as to which
such person shall have been adjudged to be liable to the corporation unless and
only to the extent that the Court of Chancery or the court in which such action
or suit was brought shall determine upon application that, despite the
adjudication of liability but in view of all the circumstances of the case, such
person is fairly and reasonably entitled to indemnity for such expenses which
the Court of Chancery or such other court shall deem proper.

                                      II-2
5

         Section 145 further provides that to the extent a present or former
director or officer of a corporation has been successful on the merits or
otherwise in the defense of any such action, suit or proceeding referred to in
subsections (a) and (b) of Section 145, or in the defense of any claim, issue or
matter therein, such person shall be indemnified against expenses (including
attorneys' fees) actually and reasonably incurred by such person in connection
therewith; that the indemnification provided for by Section 145 shall not be
deemed exclusive of any other rights which the indemnified party may be
entitled; that indemnification provided by Section 145 shall, unless otherwise
provided when authorized or ratified, continue as to a person who has ceased to
be a director, officer, employee or agent and shall inure to the benefit of such
person's heirs, executors and administrators; and empowers the corporation to
purchase and maintain insurance on behalf of any person who is or was serving at
the request of the corporation as a director, officer, employee or agent of
another corporation, partnership, joint venture, trust or other enterprise
against any liability asserted against such person and incurred by such person
in any such capacity, or arising out of such person's status as such, whether or
not the corporation would have the power to indemnify such person against such
liabilities under Section 145.

         Section 102(b)(7) of the Delaware General Corporation Law provides that
a certificate of incorporation may contain a provision eliminating or limiting
the personal liability of a director to the corporation or its stockholders for
monetary damages for breach of fiduciary duty as a director, provided that such
provision shall not eliminate or limit the liability of the director for (i) any
breach of the director's duty of loyalty to the corporation or its stockholders,
(ii) acts or omissions not in good faith or which involve intentional misconduct
or a knowing violation of law, (iii) the payment of unlawful dividends or
unlawful purchases or redemption of the corporation's stock or (iv) any
transaction from which the director derived an improper personal benefit.

         Article V of the Company's Restated Certificate of Incorporation
provides that, to the fullest extent permitted by the Delaware General
Corporation Law as the same exists or as it may hereafter be amended, no
director of the Company shall be personally liable to the Company or its
stockholders for monetary damages for breach of fiduciary duty as a director.

         Article XI of the Company's bylaws further provides that the Company
shall, to the fullest extent not prohibited by the Delaware General Corporation
Law, indemnify each of its directors and executive officers, subject to
limitations, if any, set forth in individual contracts with such directors and
executive officers and limitations on proceedings, or parts thereof, initiated
by such directors or executive officers. The Company has the power to indemnify
its other officers, employees and other agents as permitted by Delaware General
Corporation Law. The Company has entered into indemnification agreements with
each of its directors and executive officers that provide for indemnification
and expense advancement to the fullest extent permitted under the Delaware
General Corporation Law.

         The Company has purchased officers' and directors' liability insurance.

ITEM 7.           EXEMPTION FROM REGISTRATION CLAIMED

         Not Applicable.

                                      II-3
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ITEM 8.           EXHIBITS
Exhibit
         -------
3.1              Restated Certificate of Incorporation (filed as Exhibit 3.1 to the Company's
                          Quarterly Report on Form 10-Q, dated November 14, 2000).

         3.2              Bylaws (filed as Exhibit 3.2 to the Company's Registration
                          Statement on Form S-1, Registration No. 333-44529).

         4.1              1999 Network ICE Stock Option Plan.

         4.2              1995 Stock Incentive Plan (as amended and restated as of May 23, 2001).

         4.3              See Exhibits 3.1, 3.2 and the Company's Registration Statement on
                          Form 8-A, Registration No. 000-23655, together with any exhibits thereto,
                          defining the rights of holders of the Company's Common Stock.

         5.1              Opinion and consent of King & Spalding.

        23.1              Consent of Ernst & Young LLP.

        23.2              Consent of PricewaterhouseCoopers LLP., Independent Accountants

        23.3              Consent of PricewaterhouseCoopers LLP., Independent Accountants

        23.4              Consent of King & Spalding (included in Exhibit 5.1).

        24.1              Power of Attorney (included on the signature page).
ITEM 9.           UNDERTAKINGS

         (a)      The undersigned registrant hereby undertakes:

                  (1)      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 this 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 this
Registration Statement.

                                      II-4
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                           (iii) To include any material information with
respect to the plan of distribution not previously disclosed in this
Registration Statement or any material change to such information in this
Registration Statement;

provided, however, that clauses (a)(1)(i) and (a)(1)(ii) do not apply if the
information required to be included in a post-effective amendment by those
clauses 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 into this Registration
Statement.

                  (2) 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.

                  (3) 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 1999 Network ICE Stock Option Plan and the Company's Restated
1995 Stock Incentive Plan.

         (b) 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 that is incorporated by reference into this 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.

         (c) Insofar as indemnification for liabilities arising under the
Securities Act may be permitted to directors, officers or 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.

                                      II-5
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                                   SIGNATURES

         Pursuant to the requirements of the Securities Act, the Company
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 the City of Atlanta, State of Georgia on this 8th day of June,
2001.

                                INTERNET SECURITY SYSTEMS, INC.

                                By: /s/ Thomas E. Noonan
                                   ---------------------------------------------
                                   Thomas E. Noonan
                                   Chairman, President and
                                   Chief Executive Officer

                                POWER OF ATTORNEY

         KNOW ALL PERSONS BY THESE PRESENTS that each of the persons whose
signature appears below, does hereby constitute and appoint Thomas E. Noonan and
Richard Macchia and each of them, the lawful attorneys-in-fact and agents with
full power and authority to do any and all acts and things and to execute any
and all instruments which said attorneys and agents, and any one of them,
determine may be necessary or advisable or required to enable the Company to
comply with the Securities Act, and any rules or regulations or requirements of
the Commission in connection with this Registration Statement on Form S-8.
Without limiting the generality of the foregoing power and authority, the powers
granted include the power and authority to sign the names of the undersigned
officers and directors in the capacities indicated below to this Registration
Statement, to any and all amendments, both pre-effective and post-effective, and
supplements to this Registration Statement, and to any and all instruments or
documents filed as part of or in conjunction with this Registration Statement or
amendments or supplements thereof, and each of the undersigned hereby ratifies
and confirms all that said attorneys and agents, or any one of them, shall do or
cause to be done by virtue hereof. This Power of Attorney may be signed in
several counterparts.

                                      II-6
9

         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/ Thomas E. Noonan                                  Chairman, President and Chief Executive Officer   June 8, 2001
--------------------------------------------          (Principal Executive Officer)
Thomas E. Noonan

/s/ Christopher W. Klaus                              Chief Technology Officer and Director             June 8, 2001
--------------------------------------------
Christopher W. Klaus

/s/ Richard Macchia                                   Vice President and Chief Financial                June 8, 2001
--------------------------------------------          Officer (Principal Financial
Richard Macchia                                       Officer)

/s/ Maureen Richards                                  Controller (Principal Accounting Officer)         June 8, 2001
--------------------------------------------
Maureen Richards

/s/ Richard S. Bodman                                 Director                                          June 8, 2001
--------------------------------------------
Richard S. Bodman

/s/ Robert E. Davoli                                  Director                                          June 8, 2001
--------------------------------------------
Robert E. Davoli

/s/ Kevin E. O'Connor                                 Director                                          June 8, 2001
--------------------------------------------
Kevin J. O'Connor

/s/ Sam Nunn                                          Director                                          June 8, 2001
--------------------------------------------
Sam Nunn

                                                      Director
--------------------------------------------
David N. Strohm
II-7
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                                  EXHIBIT INDEX
Exhibit
         -------
3.1              Restated Certificate of Incorporation (filed as Exhibit 3.1 to the Company's
                          Quarterly Report on Form 10-Q, dated November 14, 2000).

         3.2              Bylaws (filed as Exhibit 3.2 to the Company's Registration Statement on
                          Form S-1, Registration No. 333-44529).

         4.1              1999 Network ICE Stock Option Plan.

         4.2              1995 Stock Incentive Plan (as amended and restated through May 23, 2001).

         4.3              See Exhibits 3.1, 3.2 and the Company's Registration Statement on Form 8-A,
                          Registration No. 000-23655, together with any exhibits thereto, defining the rights
                          of holders of the Company's Common Stock.

         5.1              Opinion of King & Spalding.

        23.1              Consent of Ernst & Young LLP.

        23.2              Consent of PriceWaterhouseCoopers LLP., Independent Accountants

        23.3              Consent of PricewaterhouseCoopers LLP., Independent Accountants

        23.4              Consent of King & Spalding (included in Exhibit 5.1).

        24.1              Power of Attorney (included on the signature page).
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