<PAGE>

AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON DECEMBER 24, 1999
                                                           REGISTRATION NO. 333-

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

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                                  ------------
                                    FORM S-8
                             REGISTRATION STATEMENT
                                      Under
                           The Securities Act of 1933
                                  ------------

                          CADENCE DESIGN SYSTEMS, INC.
             (Exact name of registrant as specified in its charter)

            DELAWARE                                    77-0148231
   (State or Other Jurisdiction                      (I.R.S. Employer
of Incorporation or Organization)                   Identification No.)

                          2655 SEELY AVENUE, BUILDING 5
                           SAN JOSE, CALIFORNIA 95134
               (Address of Principal Executive Offices) (Zip Code)
                             ----------------------

                 OPTIONS ASSUMED BY CADENCE DESIGN SYSTEMS, INC.
                          ORIGINALLY GRANTED UNDER THE
               DIABLO RESEARCH COMPANY LLC 1997 STOCK OPTION PLAN
           AND THE DIABLO RESEARCH COMPANY LLC 1999 STOCK OPTION PLAN
                           (Full titles of the Plans)
                             ----------------------

                              R.L. SMITH MCKEITHEN
              SENIOR VICE PRESIDENT, GENERAL COUNSEL AND SECRETARY
                          CADENCE DESIGN SYSTEMS, INC.
            2655 SEELY AVENUE, BUILDING 5, SAN JOSE, CALIFORNIA 95134
                     (Name and Address of Agent for Service)
                                 (408) 943-1234
          (Telephone number, including area code, of agent for service)
                             ----------------------
                                   COPIES TO:
                            GREGORY J. CONKLIN, ESQ.
                           GIBSON, DUNN & CRUTCHER LLP
                        ONE MONTGOMERY STREET, 26TH FLOOR
                         SAN FRANCISCO, CALIFORNIA 94104
                                 (415) 393-8200

                         CALCULATION OF REGISTRATION FEE

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

<TABLE>
<CAPTION>

Title of Securities                                    Proposed Maximum             Proposed Maximum             Amount of
 to be Registered      Amount to be Registered(1)  Offering Price per Share(2)  Aggregate Offering Price (2)  Registration Fee(2)
-------------------    --------------------------  ---------------------------  ----------------------------  -------------------

<S>                    <C>                         <C>                          <C>                           <C>

Common Stock, par            245,037 shares                   $4.73                    $1,159,025.01                $306.00
value $.01 per share

</TABLE>
================================================================================



(1)      This Registration Statement shall also cover any additional shares of
         Common Stock which become issuable under the Diablo Research Company
         LLC 1997 Stock Option Plan or the Diablo Research Company 1999 Stock
         Option Plan (together , the "Assumed Option Plans") by reason of any
         stock dividend, stock split, recapitalization or other similar
         transaction effected without the receipt of consideration which results
         in an increase in the number of the outstanding shares of Cadence
         Design Systems, Inc. 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 maximum
         offering price per share at which such options may be exercised.
================================================================================


<PAGE>


The shares of common stock subject to options registered hereunder have been
assumed by Cadence Design Systems, Inc. ("Cadence" or the "Registrant") pursuant
to an Agreement and Plan of Merger, dated as of November 19, 1999, as amended,
among Cadence, Daffodil Acquisition III, LLC, a Delaware limited liability
company and indirect wholly-owned subsidiary of Cadence, Diablo Research Company
LLC, a California limited liability company ("Diablo"), and Safeguard Pioneer,
Inc., a Delaware corporation, as securityholder agent. These options were
originally granted to directors, employees and consultants of Diablo under the
Assumed Option Plans.


<PAGE>


                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3.  INCORPORATION OF DOCUMENTS BY REFERENCE

         The Registrant hereby incorporates by reference into this Registration
Statement the following documents previously filed with the Securities and
Exchange Commission (the "Commission"):

                  (a)      The Registrant's Annual Report on Form 10-K for the
                           fiscal year ended January 2, 1999, including all
                           material incorporated by reference therein;

                  (b)      The Registrant's Quarterly Reports on Form 10-Q for
                           the fiscal quarters ended April 3, 1999, July 3, 1999
                           and October 2, 1999, including all material
                           incorporated by reference therein;

                  (c)      The Registrant's Current Report on Form 8-K/A filed
                           with the Commission on January 6, 1999;

                  (d)      The Registrant's Current Report on Form 8-K filed
                           with the Commission on May 6, 1999;

                  (e)      The Registrant's Current Report on Form 8-K/A filed
                           with the Commission on May 20, 1999;

                  (f)      The Registrant's Current Report on Form 8-K filed
                           with the Commission on May 26, 1999;

                  (g)      The Registrant's Current Report on Form 8-K/A filed
                           with the Commission on June 15, 1999;

                  (h)      The description of the Registrant's Common Stock to
                           be offered hereby contained in the Registrant's
                           Registration Statement on Form 8-A filed with the
                           Commission on August 29, 1990;

                  (i)      The description of the Registrant's Preferred Share
                           Purchase Rights set forth in Exhibit 1A, 1B and 1C to
                           the Registrant's Current Report on Form 8-A filed
                           with the Commission on February 16, 1996.

         All documents filed pursuant to Sections 13(a), 13(c), 14 or 15(d) of
the Securities Exchange Act of 1934, as amended (the "1934 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
incorporated by reference into this Registration Statement and to be a part
hereof from the date of filing of such documents.

         Any document, and 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 other subsequently filed document that
also is incorporated or deemed to be incorporated by reference herein, modifies
or supersedes such document or statement. Any such document or statement so
modified or superseded shall not be deemed, except as so modified or superseded,
to constitute a part of this Registration Statement. Subject to the foregoing,
all information appearing in this Registration Statement is qualified in its
entirety by the information appearing in the documents incorporated by
reference.


                                     II-1


<PAGE>


Item 4.  DESCRIPTION OF SECURITIES

         Not Applicable.

Item 5.  INTERESTS OF NAMED EXPERTS AND COUNSEL

         Not Applicable.

Item 6.  INDEMNIFICATION OF DIRECTORS AND OFFICERS

         Section 145 of the Delaware General Corporation Law permits a
corporation to indemnify any of its directors or officers who was or is a party
or is threatened to be made a party to any third party proceeding by reason of
the fact that such person is or was a director or officer of the corporation
against expenses (including attorneys' fees), judgments, fines and amounts paid
in settlement actually and reasonably incurred by such person in connection with
such action, suit or proceeding, if such person acted in good faith and in a
manner such 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 that such person's conduct was
unlawful. In a derivative action, i.e., one by or in the right of a corporation,
the corporation is permitted to indemnify any of its directors or officers
against expenses (including attorneys' fees) actually and reasonably incurred by
such person in connection with the defense or settlement of such action or suit
if such person acted in good faith and in a manner such person reasonably
believed to be in or not opposed to the best interests of the corporation,
except that no indemnification shall be made if such person shall have been
adjudged liable to the corporation, unless and only to the extent that the court
in which such action or suit was brought shall determine upon application that
such person is fairly and reasonably entitled to indemnity for such expenses
despite such adjudication of liability.

         Article VII of the Registrant's currently effective Certificate of
Incorporation eliminates the personal liability of its directors for monetary
damages for breach of fiduciary duty as a director, except for liability (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) under Section 174 of
the Delaware General Corporation Law or (iv) for any transaction from which the
director derived an improper personal benefit. In addition, as permitted by
Section 145 of the Delaware General Corporation Law, the Bylaws of the
Registrant provide that: (a) the Registrant is required to indemnify its
directors and officers and persons serving in such capacities in other business
entities (including, for example, subsidiaries of the Registrant) at the
Registrant's request (such directors, officers and other persons are
collectively, "Covered Persons"), to the fullest extent permitted by Delaware
law, including those circumstances in which indemnification would otherwise be
discretionary; (b) the Registrant is required to advance expenses, as incurred
to such Covered Persons in connection with defending a proceeding; (c) the
indemnitee(s) of the Registrant have the right to bring suit, and to be paid the
expenses of prosecuting such suit if successful, to enforce the rights to
indemnification under the Bylaws or to advancement of expenses under the Bylaws;
(d) the rights conferred in the Bylaws are not exclusive and the Registrant is
authorized to enter into indemnification agreements with such directors,
officers and employees; (e) the Registrant is required to maintain director and
officer liability insurance to the extent reasonably available; and (f) the
Registrant may not retroactively amend the Bylaws indemnification provision in a
way that is adverse to such Covered Persons.

         The Registrant has entered into indemnity agreements with each of its
executive officers and directors that provide the maximum indemnity allowed to
officers and directors by Section 145 of the Delaware General Corporation Law
and the Bylaws, as well as certain additional procedural protections. The
Registrant also maintains a limited amount of director and officer insurance.
The indemnification provision in the Bylaws, and the indemnity agreements
entered into between the Registrant and its officers or directors, may be
sufficiently broad to permit indemnification of the Registrant's officers and
directors for liability arising under the Securities Act of 1933, as amended
(the "1933 Act").

Item 7.  EXEMPTION FROM REGISTRATION CLAIMED

         Not Applicable.


                                     II-2


<PAGE>


Item 8.  EXHIBITS

<TABLE>
<CAPTION>

EXHIBIT NUMBER                EXHIBIT
--------------                -------

<S>     <C>
4.1(a)   The description of the Registrant's Common Stock. Reference is made to
         the Registrant's Registration Statement on Form 8-A filed with the
         Commission on August 29, 1990 incorporated by reference pursuant to
         Item 3(g);

4.1(b)   The description of the Registrant's Preferred Share Purchase Rights.
         Reference is made to Exhibit 1A, 1B and 1C to the Registrant's Current
         Report on Form 8-A filed with the Commission on February 16, 1996
         incorporated by reference pursuant to Item 3(h).

4.2      Specimen Certificate of the Registrant's Common Stock (incorporated by
         reference to Exhibit 4.01 of the Registrant's Registration Statement on
         Form S-4 (33-43400)).

4.3      Rights Agreement, dated as of February 9, 1996, between the Registrant
         and Harris Trust and Savings Bank which includes as exhibits thereto
         the Certificate of Designation for the Series A Junior Participating
         Preferred Stock, the form of Rights Certificate, and the Summary of
         Rights to Purchase Preferred Shares (incorporated by reference to
         Exhibit 1A, 1B, and 1C to the Registrant's Current Report on Form 8-K
         filed on February 16, 1996).

5.1      Opinion and consent of Gibson, Dunn & Crutcher LLP.

23.1     Consent of Arthur Andersen LLP, Independent Public Accountants.

23.2     Consent of Gibson, Dunn & Crutcher LLP (contained in Exhibit 5.1).

99.1     Diablo Research Company LLC 1997 Stock Option Plan

99.2     Diablo Research Company LLC 1999 Stock Option Plan
</TABLE>


Item 9.  UNDERTAKING

         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 1933 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; and (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 (1)(i) and (l)(ii) shall
not apply if the information required to be included in a post-effective
amendment by those paragraphs is contained in periodic reports filed by the
Registrant pursuant to Section 13 or Section 15(d) of the 1934 Act that are
incorporated by reference into this Registration Statement; (2) that for the
purpose of determining any liability under the 1933 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, and
(3) to remove from registration by means of a post-effective amendment any of
the securities being registered which remain unsold upon the termination of the
offering under the Assumed Option Plans.

         B. The undersigned Registrant hereby undertakes that, for purposes of
determining any liability under the 1933 Act, each filing of the Registrant's
annual report pursuant to Section 13(a) or Section 15(d) of the 1934 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.


                                     II-3


<PAGE>


         C. Insofar as indemnification for liabilities arising under the 1933
Act may be permitted to directors, officers or controlling persons of the
Registrant pursuant to the indemnity provisions incorporated by reference in
Item 6, or otherwise, the Registrant has been advised that in the opinion of the
Commission such indemnification is against public policy as expressed in the
1933 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 1933 Act and
will be governed by the final adjudication of such issue.



                                     II-4


<PAGE>



                                   SIGNATURES

         Pursuant to the requirements of the Securities Act of 1933, as amended,
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 the City of San Jose, State of California, on this 23rd day
of December, 1999.

                                         CADENCE DESIGN SYSTEMS, INC.

                                         By: *
                                              -----------------------------
                                         H. Raymond Bingham
                                         President, Chief Executive Officer and
                                         Director

         Pursuant to the requirements of the Securities Act of 1933, as amended,
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>
     *                                   President,  Chief Executive Officer and           December 23, 1999
----------------------------------
     H. Raymond Bingham                  Director (Principal Executive Officer)

     *                                   Senior Vice President, Chief Financial            December 23, 1999
-----------------------------------
     William Porter                      Officer (Principal Financial Officer
                                         and Principal Accounting Officer)

     *                                   Director                                          December 23, 1999
-----------------------------------
     Carol A. Bartz

     *                                   Director                                          December 23, 1999
-----------------------------------
     Dr. Leonard Y.W. Liu

     *                                   Director                                          December 23, 1999
-----------------------------------
     Donald L. Lucas

     *                                   Director                                          December 23, 1999
-----------------------------------
     Dr. Alberto Sangiovanni-
     Vincentelli

     *                                   Director                                          December 23, 1999
-----------------------------------
     George M. Scalise

     *                                   Director                                          December 23, 1999
-----------------------------------
     Dr. John B. Shoven

     *                                   Director                                          December 23, 1999
-----------------------------------
     Roger S. Siboni

By:  /s/R.L. Smith McKeithen
-----------------------------------
     R.L. Smith McKeithen
     Attorney-in-Fact

</TABLE>


                                     II-5



<PAGE>

                                            EXHIBIT INDEX

<TABLE>
<CAPTION>

EXHIBIT NUMBER             EXHIBIT
--------------             -------

<S>                       <C>
4.1(a)                     The description of the Registrant's Common Stock.
                           Reference is made to the Registrant's Registration
                           Statement on Form 8-A filed with the Commission on
                           August 29, 1990 incorporated by reference pursuant to
                           Item 3(g).

   (b)                     The description of the Registrant's Preferred Share
                           Purchase Rights. Reference is made to Exhibit 1A, 1B
                           and 1C to the Registrant's Current Report on Form 8-A
                           filed with the Commission on February 16, 1996
                           incorporated by reference pursuant to Item 3(h).

4.2                        Specimen Certificate of the Registrant's Common Stock
                           (incorporated by reference to Exhibit 4.01 of the
                           Registrant's Registration Statement on Form S-4
                           (33-43400)).

4.3                        Rights Agreement, dated as of February 9, 1996,
                           between the Registrant and Harris Trust and Savings
                           Bank which includes as exhibits thereto the
                           Certificate of Designation for the Series A Junior
                           Participating Preferred Stock, the form of Rights
                           Certificate, and the Summary of Rights to Purchase
                           Preferred Shares (incorporated by reference to
                           Exhibit 1A, 1B, and 1C to the Registrant's Current
                           Report on Form 8-K filed on February 16, 1996).

5.1                        Opinion and consent of Gibson, Dunn & Crutcher LLP.

23.1                       Consent of Arthur Andersen LLP, Independent Public
                           Accountants.

23.2                       Consent of Gibson, Dunn & Crutcher LLP (contained in
                           Exhibit 5).

99.1                       Diablo Research Company LLC 1997 Stock Option Plan

99.2                       Diablo Research Company LLC 1999 Stock Option Plan
</TABLE>
[{"type": "S-8", "sequence": "1", "description": "S-8", "secsgml_size_bytes": 23641}]
{"company-data": {"conformed-name": "CADENCE DESIGN SYSTEMS INC", "cik": "0000813672", "assigned-sic": "7372", "irs-number": "770148231", "state-of-incorporation": "DE", "fiscal-year-end": "0102"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-93609", "film-number": "99780413"}, "business-address": {"street1": "2655 SEELY ROAD BLDG 5", "city": "SAN JOSE", "state": "CA", "zip": "95134", "phone": "4089431234"}, "mail-address": {"street1": "555 RIVER OAKS PARKWAY", "city": "SAN JOSE", "state": "CA", "zip": "95134"}, "former-company": {"former-conformed-name": "ECAD INC /DE/", "date-changed": "19880609"}}
AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON DECEMBER 24, 1999
                                                           REGISTRATION NO. 333-

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

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                                  ------------
                                    FORM S-8
                             REGISTRATION STATEMENT
                                      Under
                           The Securities Act of 1933
                                  ------------

                          CADENCE DESIGN SYSTEMS, INC.
             (Exact name of registrant as specified in its charter)

            DELAWARE                                    77-0148231
   (State or Other Jurisdiction                      (I.R.S. Employer
of Incorporation or Organization)                   Identification No.)

                          2655 SEELY AVENUE, BUILDING 5
                           SAN JOSE, CALIFORNIA 95134
               (Address of Principal Executive Offices) (Zip Code)
                             ----------------------

                 OPTIONS ASSUMED BY CADENCE DESIGN SYSTEMS, INC.
                          ORIGINALLY GRANTED UNDER THE
               DIABLO RESEARCH COMPANY LLC 1997 STOCK OPTION PLAN
           AND THE DIABLO RESEARCH COMPANY LLC 1999 STOCK OPTION PLAN
                           (Full titles of the Plans)
                             ----------------------

                              R.L. SMITH MCKEITHEN
              SENIOR VICE PRESIDENT, GENERAL COUNSEL AND SECRETARY
                          CADENCE DESIGN SYSTEMS, INC.
            2655 SEELY AVENUE, BUILDING 5, SAN JOSE, CALIFORNIA 95134
                     (Name and Address of Agent for Service)
                                 (408) 943-1234
          (Telephone number, including area code, of agent for service)
                             ----------------------
                                   COPIES TO:
                            GREGORY J. CONKLIN, ESQ.
                           GIBSON, DUNN & CRUTCHER LLP
                        ONE MONTGOMERY STREET, 26TH FLOOR
                         SAN FRANCISCO, CALIFORNIA 94104
                                 (415) 393-8200

                         CALCULATION OF REGISTRATION FEE

================================================================================
Title of Securities                                    Proposed Maximum             Proposed Maximum             Amount of
 to be Registered      Amount to be Registered(1)  Offering Price per Share(2)  Aggregate Offering Price (2)  Registration Fee(2)
-------------------    --------------------------  ---------------------------  ----------------------------  -------------------
Common Stock, par            245,037 shares                   $4.73                    $1,159,025.01                $306.00
value $.01 per share
================================================================================

(1)      This Registration Statement shall also cover any additional shares of
         Common Stock which become issuable under the Diablo Research Company
         LLC 1997 Stock Option Plan or the Diablo Research Company 1999 Stock
         Option Plan (together , the "Assumed Option Plans") by reason of any
         stock dividend, stock split, recapitalization or other similar
         transaction effected without the receipt of consideration which results
         in an increase in the number of the outstanding shares of Cadence
         Design Systems, Inc. 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 maximum
         offering price per share at which such options may be exercised.
================================================================================
The shares of common stock subject to options registered hereunder have been
assumed by Cadence Design Systems, Inc. ("Cadence" or the "Registrant") pursuant
to an Agreement and Plan of Merger, dated as of November 19, 1999, as amended,
among Cadence, Daffodil Acquisition III, LLC, a Delaware limited liability
company and indirect wholly-owned subsidiary of Cadence, Diablo Research Company
LLC, a California limited liability company ("Diablo"), and Safeguard Pioneer,
Inc., a Delaware corporation, as securityholder agent. These options were
originally granted to directors, employees and consultants of Diablo under the
Assumed Option Plans.
PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3.  INCORPORATION OF DOCUMENTS BY REFERENCE

         The Registrant hereby incorporates by reference into this Registration
Statement the following documents previously filed with the Securities and
Exchange Commission (the "Commission"):

                  (a)      The Registrant's Annual Report on Form 10-K for the
                           fiscal year ended January 2, 1999, including all
                           material incorporated by reference therein;

                  (b)      The Registrant's Quarterly Reports on Form 10-Q for
                           the fiscal quarters ended April 3, 1999, July 3, 1999
                           and October 2, 1999, including all material
                           incorporated by reference therein;

                  (c)      The Registrant's Current Report on Form 8-K/A filed
                           with the Commission on January 6, 1999;

                  (d)      The Registrant's Current Report on Form 8-K filed
                           with the Commission on May 6, 1999;

                  (e)      The Registrant's Current Report on Form 8-K/A filed
                           with the Commission on May 20, 1999;

                  (f)      The Registrant's Current Report on Form 8-K filed
                           with the Commission on May 26, 1999;

                  (g)      The Registrant's Current Report on Form 8-K/A filed
                           with the Commission on June 15, 1999;

                  (h)      The description of the Registrant's Common Stock to
                           be offered hereby contained in the Registrant's
                           Registration Statement on Form 8-A filed with the
                           Commission on August 29, 1990;

                  (i)      The description of the Registrant's Preferred Share
                           Purchase Rights set forth in Exhibit 1A, 1B and 1C to
                           the Registrant's Current Report on Form 8-A filed
                           with the Commission on February 16, 1996.

         All documents filed pursuant to Sections 13(a), 13(c), 14 or 15(d) of
the Securities Exchange Act of 1934, as amended (the "1934 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
incorporated by reference into this Registration Statement and to be a part
hereof from the date of filing of such documents.

         Any document, and 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 other subsequently filed document that
also is incorporated or deemed to be incorporated by reference herein, modifies
or supersedes such document or statement. Any such document or statement so
modified or superseded shall not be deemed, except as so modified or superseded,
to constitute a part of this Registration Statement. Subject to the foregoing,
all information appearing in this Registration Statement is qualified in its
entirety by the information appearing in the documents incorporated by
reference.

                                     II-1
Item 4.  DESCRIPTION OF SECURITIES

         Not Applicable.

Item 5.  INTERESTS OF NAMED EXPERTS AND COUNSEL

         Not Applicable.

Item 6.  INDEMNIFICATION OF DIRECTORS AND OFFICERS

         Section 145 of the Delaware General Corporation Law permits a
corporation to indemnify any of its directors or officers who was or is a party
or is threatened to be made a party to any third party proceeding by reason of
the fact that such person is or was a director or officer of the corporation
against expenses (including attorneys' fees), judgments, fines and amounts paid
in settlement actually and reasonably incurred by such person in connection with
such action, suit or proceeding, if such person acted in good faith and in a
manner such 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 that such person's conduct was
unlawful. In a derivative action, i.e., one by or in the right of a corporation,
the corporation is permitted to indemnify any of its directors or officers
against expenses (including attorneys' fees) actually and reasonably incurred by
such person in connection with the defense or settlement of such action or suit
if such person acted in good faith and in a manner such person reasonably
believed to be in or not opposed to the best interests of the corporation,
except that no indemnification shall be made if such person shall have been
adjudged liable to the corporation, unless and only to the extent that the court
in which such action or suit was brought shall determine upon application that
such person is fairly and reasonably entitled to indemnity for such expenses
despite such adjudication of liability.

         Article VII of the Registrant's currently effective Certificate of
Incorporation eliminates the personal liability of its directors for monetary
damages for breach of fiduciary duty as a director, except for liability (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) under Section 174 of
the Delaware General Corporation Law or (iv) for any transaction from which the
director derived an improper personal benefit. In addition, as permitted by
Section 145 of the Delaware General Corporation Law, the Bylaws of the
Registrant provide that: (a) the Registrant is required to indemnify its
directors and officers and persons serving in such capacities in other business
entities (including, for example, subsidiaries of the Registrant) at the
Registrant's request (such directors, officers and other persons are
collectively, "Covered Persons"), to the fullest extent permitted by Delaware
law, including those circumstances in which indemnification would otherwise be
discretionary; (b) the Registrant is required to advance expenses, as incurred
to such Covered Persons in connection with defending a proceeding; (c) the
indemnitee(s) of the Registrant have the right to bring suit, and to be paid the
expenses of prosecuting such suit if successful, to enforce the rights to
indemnification under the Bylaws or to advancement of expenses under the Bylaws;
(d) the rights conferred in the Bylaws are not exclusive and the Registrant is
authorized to enter into indemnification agreements with such directors,
officers and employees; (e) the Registrant is required to maintain director and
officer liability insurance to the extent reasonably available; and (f) the
Registrant may not retroactively amend the Bylaws indemnification provision in a
way that is adverse to such Covered Persons.

         The Registrant has entered into indemnity agreements with each of its
executive officers and directors that provide the maximum indemnity allowed to
officers and directors by Section 145 of the Delaware General Corporation Law
and the Bylaws, as well as certain additional procedural protections. The
Registrant also maintains a limited amount of director and officer insurance.
The indemnification provision in the Bylaws, and the indemnity agreements
entered into between the Registrant and its officers or directors, may be
sufficiently broad to permit indemnification of the Registrant's officers and
directors for liability arising under the Securities Act of 1933, as amended
(the "1933 Act").

Item 7.  EXEMPTION FROM REGISTRATION CLAIMED

         Not Applicable.

                                     II-2
Item 8.  EXHIBITS
EXHIBIT NUMBER                EXHIBIT
--------------                -------
4.1(a)   The description of the Registrant's Common Stock. Reference is made to
         the Registrant's Registration Statement on Form 8-A filed with the
         Commission on August 29, 1990 incorporated by reference pursuant to
         Item 3(g);

4.1(b)   The description of the Registrant's Preferred Share Purchase Rights.
         Reference is made to Exhibit 1A, 1B and 1C to the Registrant's Current
         Report on Form 8-A filed with the Commission on February 16, 1996
         incorporated by reference pursuant to Item 3(h).

4.2      Specimen Certificate of the Registrant's Common Stock (incorporated by
         reference to Exhibit 4.01 of the Registrant's Registration Statement on
         Form S-4 (33-43400)).

4.3      Rights Agreement, dated as of February 9, 1996, between the Registrant
         and Harris Trust and Savings Bank which includes as exhibits thereto
         the Certificate of Designation for the Series A Junior Participating
         Preferred Stock, the form of Rights Certificate, and the Summary of
         Rights to Purchase Preferred Shares (incorporated by reference to
         Exhibit 1A, 1B, and 1C to the Registrant's Current Report on Form 8-K
         filed on February 16, 1996).

5.1      Opinion and consent of Gibson, Dunn & Crutcher LLP.

23.1     Consent of Arthur Andersen LLP, Independent Public Accountants.

23.2     Consent of Gibson, Dunn & Crutcher LLP (contained in Exhibit 5.1).

99.1     Diablo Research Company LLC 1997 Stock Option Plan

99.2     Diablo Research Company LLC 1999 Stock Option Plan
Item 9.  UNDERTAKING

         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 1933 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; and (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 (1)(i) and (l)(ii) shall
not apply if the information required to be included in a post-effective
amendment by those paragraphs is contained in periodic reports filed by the
Registrant pursuant to Section 13 or Section 15(d) of the 1934 Act that are
incorporated by reference into this Registration Statement; (2) that for the
purpose of determining any liability under the 1933 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, and
(3) to remove from registration by means of a post-effective amendment any of
the securities being registered which remain unsold upon the termination of the
offering under the Assumed Option Plans.

         B. The undersigned Registrant hereby undertakes that, for purposes of
determining any liability under the 1933 Act, each filing of the Registrant's
annual report pursuant to Section 13(a) or Section 15(d) of the 1934 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.

                                     II-3
C. Insofar as indemnification for liabilities arising under the 1933
Act may be permitted to directors, officers or controlling persons of the
Registrant pursuant to the indemnity provisions incorporated by reference in
Item 6, or otherwise, the Registrant has been advised that in the opinion of the
Commission such indemnification is against public policy as expressed in the
1933 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 1933 Act and
will be governed by the final adjudication of such issue.

                                     II-4
SIGNATURES

         Pursuant to the requirements of the Securities Act of 1933, as amended,
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 the City of San Jose, State of California, on this 23rd day
of December, 1999.

                                         CADENCE DESIGN SYSTEMS, INC.

                                         By: *
                                              -----------------------------
                                         H. Raymond Bingham
                                         President, Chief Executive Officer and
                                         Director

         Pursuant to the requirements of the Securities Act of 1933, as amended,
this Registration Statement has been signed below by the following persons in
the capacities and on the dates indicated.
SIGNATURE                                  TITLE                                  DATE
*                                   President,  Chief Executive Officer and           December 23, 1999
----------------------------------
     H. Raymond Bingham                  Director (Principal Executive Officer)

     *                                   Senior Vice President, Chief Financial            December 23, 1999
-----------------------------------
     William Porter                      Officer (Principal Financial Officer
                                         and Principal Accounting Officer)

     *                                   Director                                          December 23, 1999
-----------------------------------
     Carol A. Bartz

     *                                   Director                                          December 23, 1999
-----------------------------------
     Dr. Leonard Y.W. Liu

     *                                   Director                                          December 23, 1999
-----------------------------------
     Donald L. Lucas

     *                                   Director                                          December 23, 1999
-----------------------------------
     Dr. Alberto Sangiovanni-
     Vincentelli

     *                                   Director                                          December 23, 1999
-----------------------------------
     George M. Scalise

     *                                   Director                                          December 23, 1999
-----------------------------------
     Dr. John B. Shoven

     *                                   Director                                          December 23, 1999
-----------------------------------
     Roger S. Siboni

By:  /s/R.L. Smith McKeithen
-----------------------------------
     R.L. Smith McKeithen
     Attorney-in-Fact
II-5
EXHIBIT INDEX
EXHIBIT NUMBER             EXHIBIT
--------------             -------
4.1(a)                     The description of the Registrant's Common Stock.
                           Reference is made to the Registrant's Registration
                           Statement on Form 8-A filed with the Commission on
                           August 29, 1990 incorporated by reference pursuant to
                           Item 3(g).

   (b)                     The description of the Registrant's Preferred Share
                           Purchase Rights. Reference is made to Exhibit 1A, 1B
                           and 1C to the Registrant's Current Report on Form 8-A
                           filed with the Commission on February 16, 1996
                           incorporated by reference pursuant to Item 3(h).

4.2                        Specimen Certificate of the Registrant's Common Stock
                           (incorporated by reference to Exhibit 4.01 of the
                           Registrant's Registration Statement on Form S-4
                           (33-43400)).

4.3                        Rights Agreement, dated as of February 9, 1996,
                           between the Registrant and Harris Trust and Savings
                           Bank which includes as exhibits thereto the
                           Certificate of Designation for the Series A Junior
                           Participating Preferred Stock, the form of Rights
                           Certificate, and the Summary of Rights to Purchase
                           Preferred Shares (incorporated by reference to
                           Exhibit 1A, 1B, and 1C to the Registrant's Current
                           Report on Form 8-K filed on February 16, 1996).

5.1                        Opinion and consent of Gibson, Dunn & Crutcher LLP.

23.1                       Consent of Arthur Andersen LLP, Independent Public
                           Accountants.

23.2                       Consent of Gibson, Dunn & Crutcher LLP (contained in
                           Exhibit 5).

99.1                       Diablo Research Company LLC 1997 Stock Option Plan

99.2                       Diablo Research Company LLC 1999 Stock Option Plan