As filed with the Securities and Exchange Commission on September 28, 1999
                                                  Registration No. 333- ______
- -------------------------------------------------------------------------------

                       SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549
                      ------------------------------------

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

                            INTEGRATED SYSTEMS, INC.
             (Exact name of Registrant as specified in its charter)

       California                                    94-2658153
 (State of Incorporation)                 (I.R.S. Employer Identification No.)

               201 Moffett Park Drive, Sunnyvale, California 94089
           (Address of Principal Executive Office Including Zip Code)

                            INTEGRATED SYSTEMS, INC.
                           1998 EQUITY INCENTIVE PLAN
                        1999 EMPLOYEE STOCK PURCHASE PLAN
                        ---------------------------------
                            (Full title of the plan)

                              Charles M. Boesenberg
                      President and Chief Executive Officer
                            Integrated Systems, Inc.
                             201 Moffett Park Drive
                           Sunnyvale, California 94089
                                 (408) 542-1500
            (Name, address and telephone number of agent for service)

                                    Copy to:
                            Katherine Tallman Schuda
                               Fenwick & West LLP
                              Two Palo Alto Square
                               Palo Alto, CA 94306




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                         CALCULATION OF REGISTRATION FEE

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                                                Proposed
                                                Maximum
Title of                 Amount                 Offering               Proposed Maximum
Securities to            to be                  Price per              Aggregate Offering     Amount of
Be Registered            Registered             Share (1)              Price                  Registration Fee
- --------------------------------------------------------------------------------------------- ----------------------
                                                                                  
Common Stock             1,800,000              $11.99                 $21,582,000            $6,000.00
- --------------------------------------------------------------------------------------------------------------------


(1)       Estimated solely for the purpose of calculating the registration fee
          in accordance with Rules 457(h) and 457(c) under the Securities Act of
          1933 and based upon an average of the high and low prices reported on
          the Nasdaq National Market on September 22, 1999.





                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3.  INCORPORATION OF DOCUMENTS BY REFERENCE.

         The following documents filed with the Securities and Exchange
Commission (the "Commission") are incorporated by reference in this Registration
Statement:

         1.   The Registrant's Annual Report on Form 10-K for the fiscal year
ended February 28, 1999, filed pursuant to Section 13(a) of the Securities
Exchange Act of 1934, as amended (the "Exchange Act"), which Annual Report
contains audited financial statements for the fiscal year ended February 28,
1999;

         2.   The Registrant's Quarterly Report on Form 10-Q for the fiscal
quarter ended May 31, 1999 filed pursuant to Section 13(a) of the Exchange Act;

         3.   The Registrant's Current Report on Form 8-K dated July 21, 1999;
and

         4.   The description of the Registrant's Common Stock contained in the
Registrant's Registration Statement on Form 8-A filed with the Commission under
Section 12(g) of the Exchange Act, including any amendment or report filed for
the purpose of updating such description.

         All documents filed by the Registrant pursuant to Sections 13(a),
13(c), 14 and 15(d) of 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 registered hereby have been sold or which deregisters all
securities then remaining unsold, shall be deemed to be incorporated by
reference in this Registration Statement and to be a part hereof from the date
of the filing of such documents.

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 provisions of Section 317 of the California Corporations Code,
Article V of the Registrant's Amended and Restated Articles of Incorporation and
Article VI of the Registrant's Bylaws provide for indemnification for expenses,
judgments, fines, settlements and other amounts actually and reasonably incurred
in connection with any proceeding arising by reason of the fact that any person
is or was a director or officer of the Registrant. The Registrant's directors
and executive officers have also entered into Indemnity Agreements with the
Registrant that give such directors and executive officers contractual
assurances regarding the scope of the indemnification and liability limitations
set forth in the Registrant's Amended and Restated Articles of Incorporation and
Bylaws. The indemnification may be sufficiently broad to permit indemnification
of the Registrant's executive officers and directors for liabilities arising
under the Securities Act. In addition, Article IV of the Registrant's Amended
and Restated Articles of Incorporation provides that the liability of the
Registrant's directors shall be eliminated to the fullest extent permissible
under California law. The Registrant maintains a director and officer liability
insurance policy.

         Insofar as indemnification for liabilities arising under the Act may be
permitted to directors, officers or controlling persons of the Company pursuant
to the foregoing provisions, the Company has been informed that, in


                                      II-1


the opinion of the Securities and Exchange Commission, such indemnification is
against public policy as expressed in the Act and is therefore unenforceable.

Item 7.  EXEMPTION FROM REGISTRATION CLAIMED.

         Not applicable.

Item 8.  EXHIBITS.

The following exhibits are filed herewith:

Exhibit No.        Description
- -----------        -----------

4.01               Registrant's Amended and Restated Articles of Incorporation
                   (incorporated by reference to Exhibit 3.01(i) to the
                   Registrant's Annual Report on Form 10-K for the fiscal year
                   ended February 28, 1996).

4.02               Registrant's Bylaws, as amended (incorporated by reference
                   to Exhibit 4.02 to the Registrant's Registration Statement
                   on Form S-8, File No. 333-12799).

4.03               Registrant's 1999 Employee Stock Purchase Plan.

4.04               Registrant's 1998 Equity Incentive Plan and related
                   documents.

4.05               Certificate of Amendment of Bylaws

5.01               Opinion of Fenwick & West LLP

23.01              Consent of Counsel (included in Exhibit 5.01)

23.02              Consent of PricewaterhouseCoopers LLP

24.01              Power of Attorney (See page II-5)


Item 9.  UNDERTAKINGS.

         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:

                 (a)   To include any prospectus required by Section 10(a)(3)
          of the Securities Act of 1933;

                  (b)   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 thereto) which, individually or in
          the aggregate, represent a fundamental change in the information set
          forth in the registration statement. Notwithstanding the foregoing,
          any increase or decrease in volume of securities offered (if the
          total dollar value of securities offered would not exceed that
          which was registered) and any deviation from the low or high end of
          the estimated maximum offering range may be reflected in the form
          of prospectus filed with the Commission pursuant to Rule 424(b) if,
          in the aggregate, the changes in volume and price represent no more
          than a 20 percent change in the maximum aggregate offering price
          set forth in the "Calculation of Registration Fee" table in the
          effective registration statement;

                  (c) 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.

                                      II-2


         Provided, however, that paragraphs (1)(a) and (1)(b) 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
Securities Exchange Act of 1934 that are incorporated by reference in the
registration statement.

         (2) That, for the purpose of determining any liability under the
Securities Act of 1933, 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 offering.

         (4) That, for purposes of determining any liability under the
Securities Act of 1933, each filing of the registrant's annual report pursuant
to Section 13(a) or Section 15(d) of the Securities Exchange Act of 1934 (and,
where applicable, each filing of an employee benefit plan's annual report
pursuant to Section 15(d) of the Securities Exchange Act of 1934) 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.

         (5) To deliver or cause to be delivered with the prospectus, to each
person to whom the prospectus is sent or given, the latest annual report to
security holders that is incorporated by reference in the prospectus and
furnished pursuant to and meeting the requirements of Rule 14a-3 or Rule 14c-3
under the Securities Exchange Act of 1934; and, where interim financial
information required to be presented by Article 3 of Regulation S-X is not set
forth in the prospectus, to deliver, or cause to be delivered to each person to
whom the prospectus is sent or given, the latest quarterly report that is
specifically incorporated by reference in the prospectus to provide such interim
financial information.

         (6) Insofar as indemnification for liabilities arising under the
Securities Act of 1933 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 Securities and
Exchange Commission such indemnification is against public policy as expressed
in the 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 Act and will
be governed by the final adjudication of such issue.


                                      II-3


                                   SIGNATURES

         Pursuant to the requirements of the Securities Act of 1933, the
registrant, Integrated Systems, Inc., 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 Sunnyvale, State of
California, on September 24, 1998.

                                      INTEGRATED SYSTEMS, INC.


                                      By:  /s/ William C. Smith
                                           -----------------------------------
                                           William C. Smith
                                           Vice President, Finance
                                           and Chief Financial Officer


                                      II-4


                                POWER OF ATTORNEY

         Each person whose signature appears below constitutes and appoints
Charles M. Boesenberg and William C. Smith and each of them, his true and lawful
attorneys-in-fact and agents, each with full power of substitution, for him and
in his name, place and stead, in any and all capacities, to sign any and all
amendments (including post-effective amendments) to this Registration Statement
and to file the same, with exhibits thereto and all other documents in
connection therewith, with the Securities and Exchange Commission, granting to
said attorneys-in-fact and agents, and each of them, full power and authority to
do and perform each and every act and thing requisite and necessary to be done
in connection therewith, as fully to all intents and purposes as he might or
could do in person, hereby ratifying and confirming all that said
attorneys-in-fact and agents or either of them, or their or his substitute or
substitutes, may lawfully do or cause to be done by virtue hereof.

         Pursuant to the requirements of the Securities Act of 1933, this
registration statement has been signed by the following persons in the
capacities and on the dates indicated.




Signature                                   Title                                    Date
- ----------------------------------------    -------------------------------------    -------------------------------------
Principal Executive Officer:
                                                                               
/s/ Charles M. Boesenberg                   President, Chief Executive Officer       September 24, 1999
- ------------------------------------        and Director
Charles M. Boesenberg

Principal Financial Officer and
Principal Accounting Officer:

/s/ William C. Smith                        Vice President, Finance and Chief        September 24, 1999
- ------------------------------------        Financial Officer
William C. Smith

Additional Directors:

/s/ Narendra K. Gupta                       Chairman of the Board of Directors       September 24, 1999
- ------------------------------------
Narendra K. Gupta

/s/ Thomas Kailath                          Director                                 September 24, 1999
- ------------------------------------
Thomas Kailath

/s/ Vinita Gupta                            Director                                 September 24, 1999
- ------------------------------------
Vinita Gupta

/s/John C. Bolger                           Director                                 September 24, 1999
- ------------------------------------
John C. Bolger

/s/Richard C. Murphy                        Director                                 September 24, 1999
- ------------------------------------
Richard C. Murphy

/s/Michael A. Brochu                        Director                                 September 24, 1999
- ------------------------------------
Michael A. Brochu

/s/James E.Challenger                       Director                                 September 24, 1999
- ------------------------------------
James E. Challenger



                                      II-5


                                INDEX TO EXHIBITS




Exhibit Number     Exhibit
- --------------     --------
                
4.01               Registrant's Amended and Restated Articles of Incorporation
                   (incorporated by reference to Exhibit 3.01(i) to the
                   Registrant's Annual Report on Form 10-K for the fiscal year
                   ended February 28, 1996).

4.02               Registrant's Bylaws, as amended (incorporated by reference
                   to Exhibit 4.02 to the Registrant's Registration Statement
                   on Form S-8, File No. 333-12799)

4.03               Registrant's 1999 Employee Stock Purchase Plan.

4.04               Registrant's 1998 Equity Incentive Plan and related
                   documents.

4.05               Certificate of Amendment of Bylaws

5.01               Opinion of Fenwick & West LLP

23.01              Consent of Counsel (included in Exhibit 5.01)

23.02              Consent of PricewaterhouseCoopers LLP

24.01              Power of Attorney (See page II-5)