<SUBMISSION>
<ACCESSION-NUMBER>0000950134-04-011426
<TYPE>424B3
<PUBLIC-DOCUMENT-COUNT>1
<FILING-DATE>20040805
<FILER>
<COMPANY-DATA>
<CONFORMED-NAME>CADENCE DESIGN SYSTEMS INC
<CIK>0000813672
<ASSIGNED-SIC>7372
<IRS-NUMBER>770148231
<STATE-OF-INCORPORATION>DE
<FISCAL-YEAR-END>0102
</COMPANY-DATA>
<FILING-VALUES>
<FORM-TYPE>424B3
<ACT>33
<FILE-NUMBER>333-110346
<FILM-NUMBER>04954680
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>2655 SEELY ROAD BLDG 5
<CITY>SAN JOSE
<STATE>CA
<ZIP>95134
<PHONE>4089431234
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>555 RIVER OAKS PARKWAY
<CITY>SAN JOSE
<STATE>CA
<ZIP>95134
</MAIL-ADDRESS>
<FORMER-COMPANY>
<FORMER-CONFORMED-NAME>ECAD INC /DE/
<DATE-CHANGED>19880609
</FORMER-COMPANY>
</FILER>
<DOCUMENT>
<TYPE>424B3
<SEQUENCE>1
<FILENAME>f00907b3e424b3.htm
<DESCRIPTION>424B3
<TEXT>
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<DIV style="font-family: 'Times New Roman',Times,serif">


<P align="center" style="font-size: 10pt"><B>Filed under Rule&nbsp;424(b)(3) of the Securities Act of 1933,<BR>
relating to Registration No.&nbsp;333-110346</B>



<P align="center" style="font-size: 10pt"><B>Prospectus Supplement No.&nbsp;6<BR>
to Prospectus Dated April&nbsp;29, 2004<BR>
of</B>


<P align="center" style="font-size: 24pt"><B>CADENCE DESIGN SYSTEMS, INC.</B>


<P align="center" style="font-size: 10pt"><B>Relating to</B>



<P align="center" style="font-size: 10pt"><B>$420,000,000 Zero Coupon Zero Yield Senior Convertible Notes due 2023<BR>
and<BR>
Shares of Common Stock Issuable upon Conversion of the Notes</B>



<P align="left" style="font-size: 10pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;This prospectus supplement no. 6 relates to the resale by selling
securityholders of Cadence Design Systems, Inc.&#146;s Zero Coupon Zero Yield Senior
Convertible Notes Due 2023 and the shares of Cadence common stock issuable upon
conversion of the notes.


<P align="left" style="font-size: 10pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;You should read this prospectus supplement no. 6 in conjunction with the
prospectus dated April&nbsp;29, 2004, which should be delivered in conjunction with
this prospectus supplement. This prospectus supplement is not complete without,
and may not be delivered or used except in conjunction with, the prospectus,
including any amendments or supplements to it. This prospectus supplement is
qualified by reference to the prospectus, except to the extent that the
information provided by this prospectus supplement supercedes information
contained in the prospectus.


<P align="left" style="font-size: 10pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<B>Investing in the notes and the common stock issuable upon conversion of
the notes involves risk. See the discussion entitled &#147;Risk Factors&#148; beginning
on page 6 of the prospectus dated April&nbsp;29, 2004.</B>


<P align="left" style="font-size: 10pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<B>Neither the Securities and Exchange Commission nor any state securities
commission has approved or disapproved of these securities or passed upon the
adequacy or accuracy of this prospectus supplement or the prospectus dated
April&nbsp;29, 2004. Any representation to the contrary is a criminal offense.</B>


<P align="left" style="font-size: 10pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;The table under the caption &#147;Selling Securityholders&#148; beginning on page 51
of the prospectus is hereby supplemented and amended by adding to it certain
selling securityholders identified in the table below. We prepared this table
based on information supplied to us by the selling securityholders named in the
table below on or prior to August&nbsp;5, 2004. Information about the selling
securityholders may change over time. If required, any changed or new
information given to us will be set forth in supplements to the prospectus or
amendments to the registration statement of which this prospectus is a part, if
and when necessary.


<P align="left" style="font-size: 10pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;We have assumed for purposes of the table below that the selling
securityholders will sell all of the notes and all of the common stock issuable
upon conversion of the notes pursuant to this prospectus supplement and the
prospectus, and that any other shares of our common stock beneficially owned by
the selling securityholders will continue to be beneficially owned.


<P align="center" style="font-size: 10pt">&nbsp;
</DIV>

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<DIV style="font-family: 'Times New Roman',Times,serif">

<P align="left" style="font-size: 10pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Except as set forth below, none of the selling securityholders has, or
within the past three years has had, any position, office or other material
relationship with us or any of our predecessors or affiliates.


<P align="left" style="font-size: 10pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;The selling securityholders identified below may have sold, transferred or
otherwise disposed of, pursuant to transactions exempt from the registration
requirements of the Securities Act of 1933, as amended, all or a portion of
their notes since the date on which they provided the information regarding
their notes.

<DIV align="center">
<TABLE style="font-size: 10pt" cellspacing="0" border="0" cellpadding="0" width="100%">
<!-- Begin Table Head -->
<TR valign="bottom">
    <TD width="21%">&nbsp;</TD>
    <TD width="3%">&nbsp;</TD>
    <TD width="5%">&nbsp;</TD>
    <TD width="1%">&nbsp;</TD>
    <TD width="6%">&nbsp;</TD>
    <TD width="3%">&nbsp;</TD>
    <TD width="1%">&nbsp;</TD>
    <TD width="1%">&nbsp;</TD>
    <TD width="2%">&nbsp;</TD>
    <TD width="3%">&nbsp;</TD>
    <TD width="5%">&nbsp;</TD>
    <TD width="1%">&nbsp;</TD>
    <TD width="5%">&nbsp;</TD>
    <TD width="3%">&nbsp;</TD>
    <TD width="5%">&nbsp;</TD>
    <TD width="1%">&nbsp;</TD>
    <TD width="5%">&nbsp;</TD>
    <TD width="3%">&nbsp;</TD>
    <TD width="1%">&nbsp;</TD>
    <TD width="1%">&nbsp;</TD>
    <TD width="1%">&nbsp;</TD>
    <TD width="3%">&nbsp;</TD>
    <TD width="20%">&nbsp;</TD>
</TR>
<TR style="font-size: 8pt" valign="bottom">
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="3"><B>Number of</B></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center"><B>&nbsp;</B></TD>
</TR>
<TR style="font-size: 8pt" valign="bottom">
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="3"><B>Number of</B></TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="3"><B>Shares of</B></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center"><B>&nbsp;</B></TD>
</TR>
<TR style="font-size: 8pt" valign="bottom">
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="3"><B>Principal</B></TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="3"><B>Shares of</B></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="3"><B>Number of</B></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="3"><B>Common Stock</B></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center"><B>Natural</B></TD>
</TR>
<TR style="font-size: 8pt" valign="bottom">
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="3"><B>Amount of Notes</B></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="3"><B>Percentage of</B></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="3"><B>Common Stock</B></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="3"><B>Shares of</B></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="3"><B>Beneficially Owned</B></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center"><B>Person(s) with</B></TD>
</TR>
<TR style="font-size: 8pt" valign="bottom">
    <TD nowrap align="left"><B>Name of Selling</B></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="3"><B>Beneficially</B></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="3"><B>Notes</B></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="3"><B>Beneficially</B></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="3"><B>Common Stock</B></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="3"><B>after the</B></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center"><B>Voting or</B></TD>
</TR>
<TR style="font-size: 8pt" valign="bottom">
    <TD nowrap align="left"><B>Securityholder</B><HR size="1" noshade></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="3"><B>Owned and Offered</B><HR size="1" noshade></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="3"><B>Outstanding</B><HR size="1" noshade></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="3"><B>Owned(1)(2)</B><HR size="1" noshade></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="3"><B>Offered (1)</B><HR size="1" noshade></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="3"><B>Offering(2)(3)</B><HR size="1" noshade></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center"><B>Investment Power</B><HR size="1" noshade></TD>
</TR>

<!-- End Table Head -->
<!-- Begin Table Body -->
<TR valign="bottom">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">McMahan Securities
Co., L.P. #
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="right" valign="top">$</TD>
    <TD align="right" valign="top">149,000</TD>
    <TD nowrap valign="top">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="right" valign="top">&nbsp;</TD>
    <TD align="right" valign="top">*</TD>
    <TD nowrap valign="top">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="right" valign="top">&nbsp;</TD>
    <TD align="right" valign="top">9,517</TD>
    <TD nowrap valign="top">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="right" valign="top">&nbsp;</TD>
    <TD align="right" valign="top">9,517</TD>
    <TD nowrap valign="top">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="right" valign="top">&nbsp;</TD>
    <TD align="right" valign="top">0</TD>
    <TD nowrap valign="top">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">D. Bruce McMahan,
Scott Dillinger,
Jay T. Glassman,
Ronald P. Fertig,
Patricia Ransom,
and Norman L.
Ziegler</TD>
</TR>
<TR><TD>&nbsp;</TD></TR>
<TR valign="bottom">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">Highbridge<BR>
International LLC &#043;
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="right" valign="top">&nbsp;</TD>
    <TD align="right" valign="top">36,500,000</TD>
    <TD nowrap valign="top">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="right" valign="top">&nbsp;</TD>
    <TD align="right" valign="top">8.69</TD>
    <TD nowrap valign="top">%</TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="right" valign="top">&nbsp;</TD>
    <TD align="right" valign="top">2,331,583</TD>
    <TD nowrap valign="top">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="right" valign="top">&nbsp;</TD>
    <TD align="right" valign="top">2,331,583</TD>
    <TD nowrap valign="top">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="right" valign="top">&nbsp;</TD>
    <TD align="right" valign="top">0</TD>
    <TD nowrap valign="top">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">Glenn Dubin and
Henry Sweca</TD>
</TR>

<!-- End Table Body -->
</TABLE>
</DIV>




<P>
<HR size="1" width="18%" align="left" noshade>

<TABLE width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt">

<TR valign="top">
    <TD width="1%" nowrap align="right">*</TD>
    <TD width="3%">&nbsp;</TD>
    <TD width="96%">Less than one percent (1%).</TD>
</TR>

<TR><TD>&nbsp;</TD></TR>

<TR valign="top">
    <TD width="1%" nowrap align="right">#</TD>
    <TD width="3%">&nbsp;</TD>
    <TD width="96%">The selling securityholder is a registered broker-dealer.</TD>
</TR>

<TR><TD>&nbsp;</TD></TR>

<TR valign="top">
    <TD width="1%" nowrap align="right">&#043;</TD>
    <TD width="3%">&nbsp;</TD>
    <TD width="96%">The selling securityholder is an affiliate of a registered broker-dealer.</TD>
</TR>

<TR><TD>&nbsp;</TD></TR>

<TR valign="top">
    <TD width="1%" nowrap align="right">(1)</TD>
    <TD width="3%">&nbsp;</TD>
    <TD width="96%">Assumes conversion of all of the holder&#146;s notes at a conversion rate of
63.8790 shares of common stock per $1,000 principal amount at maturity of the
notes. This conversion rate is subject to adjustment as described under
''Description of Notes &#151; Conversion Rights&#146;&#146; in the prospectus dated April&nbsp;29,
2004. As a result, the number of shares of common stock issuable upon
conversion of the notes may increase or decrease in the future. Excludes shares
of common stock that may be issued by us upon the repurchase of the notes as
described under ''Description of Notes &#151;  Repurchase of the Notes by Us at the
Option of Holders Upon a Fundamental Change&#146;&#146; in the prospectus and fractional
shares. Holders will receive a cash adjustment for any fractional share amount
resulting from conversion of the notes, as described under ''Description of
Notes &#151; Conversion Rights&#146;&#146; in the prospectus.</TD>
</TR>

<TR><TD>&nbsp;</TD></TR>

<TR valign="top">
    <TD width="1%" nowrap align="right">(2)</TD>
    <TD width="3%">&nbsp;</TD>
    <TD width="96%">The number of shares of common stock beneficially owned by each holder
named above is less than 1% of our outstanding common stock, calculated based
on 273,356,132 shares of common stock outstanding as of April&nbsp;3, 2004. In
calculating this amount for each holder, we treated as outstanding the number
of shares of common stock issuable upon conversion of all of that holder&#146;s
notes, but we did not assume conversion of any other holder&#146;s notes.</TD>
</TR>

<TR><TD>&nbsp;</TD></TR>

<TR valign="top">
    <TD width="1%" nowrap align="right">(3)</TD>
    <TD width="3%">&nbsp;</TD>
    <TD width="96%">For the purposes of computing the number and percentage of notes and shares
to be held by the selling shareholders after the conclusion of the offering, we
have assumed for purposes of the table above that the selling</TD>
</TR>

</TABLE>



<P align="center" style="font-size: 10pt">2
</DIV>

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<H5 align="left" style="page-break-before:always">&nbsp;</H5><P>

<DIV style="font-family: 'Times New Roman',Times,serif">



<TABLE width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt">

<TR valign="top">
    <TD width="1%" nowrap align="right">&nbsp;</TD>
    <TD width="3%">&nbsp;</TD>
    <TD width="96%">securityholders named above will sell all of the notes and all of the common
stock issuable upon conversion of the notes offered by this prospectus
supplement and the prospectus, and that any other shares of our common stock
beneficially owned by these selling securityholders will continue to be
beneficially owned.</TD>
</TR>

</TABLE>



<P align="left" style="font-size: 10pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;The last sentence of the ninth paragraph of the section of the prospectus
entitled &#147;Plan of Distribution&#148; is hereby amended and restated in its entirety
to read as follows:


<P align="left" style="font-size: 10pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;We have been informed that the selling securityholders identified by the
symbol # in the table in the preceding section &#147;Selling Securityholders&#148; (Bear,
Stearns &#038; Co., Inc., Forest Fulcrum Fund LP, Goldman, Sachs &#038; Co., J.P. Morgan
Securities Inc., KBC Financial Products USA Inc., McMahan Securities Co., L.P.,
Nomura Securities International, Inc., TD Securities (USA)&nbsp;Inc., Wachovia
Capital Markets LLC and White River Securities L.L.C.) are registered
broker-dealers, and as a result they are underwriters in connection with the
sale of the notes and the underlying common stock.


<P align="left" style="font-size: 10pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;The tenth paragraph of the section of the prospectus entitled &#147;Plan of
Distribution&#148; is hereby amended and restated in its entirety to read as
follows:


<P align="left" style="font-size: 10pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Each of the selling securityholders identified by the symbol &#147;&#043;&#148; in the
table in the preceding section &#147;Selling Securityholders&#148; (Amaranth L.L.C., BNP
Paribas Equity Strategies, SNC, Canyon Capital Arbitrage Master Fund, Ltd.,
Canyon Value Realization Fund (Cayman) Ltd., Canyon Value Realization Fund,
L.P., Canyon Value Realization MAC 18, Ltd., Common Fund Event Driven Co.,
Ltd., Credit Suisse First Boston Europe Limited, Grace Convertible Arbitrage
Fund, Ltd., Highbridge International LLC, KBC Financial Products (Cayman
Islands) Ltd., Levco Alternative Fund, Ltd., Lyxor/JLC Fund, Ltd., Purchase
Associates, L.P., Purchase Associates II, L.P., R2 Investments LDC, Royal Bank
of Canada, St. Thomas Trading, Ltd., Sunrise Partners Limited Partnership and
UBS AG London Branch) has informed us that it is an affiliate of one or more
registered broker-dealers. Each of these selling securityholders has also
informed us that: (1)&nbsp;such selling securityholder purchased its notes in the
ordinary course of business and (2)&nbsp;at the time the notes were purchased, the
selling securityholder had no agreements or understandings, directly or
indirectly, with any person to distribute the notes.


<P align="left" style="font-size: 10pt">The date of this prospectus supplement is August&nbsp;5, 2004.




<P align="center" style="font-size: 10pt">3
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