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     AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON MAY 1, 1996
                                               REGISTRATION NO. 333-
================================================================================
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                                ---------------
                                    FORM S-3
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933
                            INTEGRATED SYSTEMS, INC.
             (Exact name of Registrant as specified in its charter)

         CALIFORNIA                                             94-2658153
(State or other jurisdiction of                             (I.R.S. employer
incorporation or organization)                              identification no.)
                                ---------------
                             201 MOFFETT PARK DRIVE
                           SUNNYVALE, CALIFORNIA 94089
                                 (408) 542-1500
               (Address, including zip code, and telephone number,
        including area code, of Registrant's principal executive offices)
                                ---------------
                    NARENDRA K. GUPTA, CHAIRMAN OF THE BOARD
                            INTEGRATED SYSTEMS, INC.
                             201 MOFFETT PARK DRIVE
                           SUNNYVALE, CALIFORNIA 94089
                                 (408) 542-1500
            (Name, address, including zip code, and telephone number,
                   including area code, of agent for service)
                                ---------------
                                   Copies to:

  LAIRD H. SIMONS III, ESQ.                          WILLIAM D. SHERMAN, ESQ.
   FRED M. GREGURAS, ESQ.                           JOHN W. CAMPBELL III, ESQ.
 KATHERINE T. TALLMAN, ESQ.                             CORI M. ALLEN, ESQ.
     MONA CHANDRA, ESQ.                               MORRISON & FOERSTER LLP
     FENWICK & WEST LLP                                 755 PAGE MILL ROAD
    TWO PALO ALTO SQUARE                            PALO ALTO, CALIFORNIA 94304
PALO ALTO, CALIFORNIA  94306                              (415) 813-5600
       (415) 494-0600
                                ---------------
        APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC:
As soon as practicable after the effective date of this Registration Statement.
                                ---------------
         If the only securities being registered on this Form are being offered
pursuant to dividend or interest reinvestment plans, please check the following
box. / /

         If any of the securities being registered on this Form are to be
offered on a delayed or continuous basis pursuant to Rule 415 under the
Securities Act of 1933, other than securities offered only in connection with
dividend or interest reinvestment plans, check the following box. / /

         If this Form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act, please check the following box
and list the Securities Act registration statement number of the earlier
effective registration statement for the same offering. /X/ 333-02449

         If this Form is a post-effective amendment filed pursuant to Rule
462(c) under the Securities Act, check the following box and list the Securities
Act registration statement number of the earlier effective registration
statement for the same offering. / /

         If delivery of the prospectus is expected to be made pursuant to Rule
434, please check the following box. / /

                         CALCULATION OF REGISTRATION FEE


- ----------------------------------------------------------------------------------------------------------------------------------
 TITLE OF EACH CLASS OF SECURITIES     AMOUNT TO BE        OFFERING PRICE PER          AGGREGATE OFFERING             AMOUNT OF
          TO BE REGISTERED             REGISTERED(1)              SHARE                      PRICE                REGISTRATION FEE
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     Common Stock, no par value        115,000 shs.              $28.00                    $3,220,000                 $1,110.34
- ----------------------------------------------------------------------------------------------------------------------------------


(1)      Includes 15,000 shares that the Underwriters have the option to
         purchase to cover over-allotments, if any.
                                ---------------
         THE REGISTRANT HEREBY AMENDS THIS REGISTRATION STATEMENT ON SUCH DATE
OR DATES AS MAY BE NECESSARY TO DELAY ITS EFFECTIVE DATE UNTIL THE REGISTRANT
SHALL FILE A FURTHER AMENDMENT WHICH SPECIFICALLY STATES THAT THIS REGISTRATION
STATEMENT SHALL THEREAFTER BECOME EFFECTIVE IN ACCORDANCE WITH SECTION 8(a) OF
THE SECURITIES ACT OF 1933 OR UNTIL THE REGISTRATION STATEMENT SHALL BECOME
EFFECTIVE ON SUCH DATE AS THE COMMISSION, ACTING PURSUANT TO SAID SECTION 8(a),
MAY DETERMINE.

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In accordance with General Instruction IV to Form S-3 and Rule 462(b)
promulgated under the Securities Act of 1933, this Registration Statement
incorporated by reference the contents of Registration Statement No. 333-02449
filed with the Securities and Exchange Commission on April 12, 1996.

EXHIBITS.

The following exhibits are filed herewith:

 EXHIBIT
  NUMBER                                      EXHIBIT TITLE
  ------                                      -------------

   5.01  - Opinion of Fenwick & West LLP regarding legality of the securities
           being issued.

  23.01  - Consent of Fenwick & West LLP (included in Exhibit 5.01).

  23.02  - Consent of Coopers & Lybrand L.L.P., Independent Accountants.

  24.1   - Power of Attorney (incorporated by reference from page II-4 of the
           Registration Statement on Form S-3 (File No. 333-02449)).


                                      II-1
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                                   SIGNATURES

         In accordance with 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-3 and authorized this Registration
Statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the City of Sunnyvale, State of California, on April 30, 1996.

                                      INTEGRATED SYSTEMS, INC.

                                      By:  /s/  Steven Sipowicz
                                           ---------------------------------
                                           Steven Sipowicz
                                           Vice President, Finance and Chief
                                             Financial Officer

                                POWER OF ATTORNEY

         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.



         NAME                                        TITLE                                   DATE
                                                                                    
PRINCIPAL EXECUTIVE OFFICER:

/s/ David P. St. Charles*               President, Chief Executive Officer                April 30, 1996
- ---------------------------             and Director
David P. St. Charles                    

PRINCIPAL FINANCIAL AND ACCOUNTING OFFICER:

/s/ Steven Sipowicz                     Vice President, Finance and                       April 30, 1996
- ---------------------------             Chief Financial Officer
Steven Sipowicz                         

ADDITIONAL DIRECTORS:

/s/ Narendra K. Gupta*                  Chairman of the Board and Secretary               April 30, 1996
- ---------------------------
Narendra K. Gupta

/s/ John C. Bolger*                     Director                                          April 30, 1996
- ---------------------------
John C. Bolger

/s/ Vinita Gupta*                       Director                                          April 30, 1996
- ---------------------------
Vinita Gupta

/s/ Thomas Kailath*                     Director                                          April 30, 1996
- ---------------------------
Thomas Kailath

/s/ Richard C. Murphy*                  Director                                          April 30, 1996
- ---------------------------
Richard C. Murphy

*By:   /s/ Steven Sipowicz
    -----------------------
       Steven Sipowicz
       Attorney-in-fact



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                                EXHIBIT INDEX


 EXHIBIT
  NUMBER                        EXHIBIT TITLE
  ------                        -------------

   5.01  - Opinion of Fenwick & West LLP regarding legality of the securities
           being issued.

  23.01  - Consent of Fenwick & West LLP (included in Exhibit 5.01).

  23.02  - Consent of Coopers & Lybrand L.L.P., Independent Accountants.

  24.1   - Power of Attorney (incorporated by reference from page II-4 of the
           Registration Statement on Form S-3 (File No. 333-02449)).