Glass Lewis & Co. and Egan-Jones Proxy Services, two leading proxy advisory firms, recently issued reports supporting your Board and its nominees. Both firms recommend that shareholders vote for ALL of Mentor Graphics’ nominees and reject all of Icahn’s nominees. Another proxy advisory firm, Institutional Shareholder Services (ISS), provided a split recommendation for two of the three Icahn nominees, which we believe reflects ISS’s general tendency of supporting minority representation for shareholder activists, as well as a failure to analyze Icahn’s stated plan to pursue a public sale of the company.

DO NOT BE PERSUADED BY ICAHN’S PLATFORM OF A PUBLIC SALE PROCESS WITH ITS SIGNIFICANT REGULATORY AND COMMERCIAL RISK — IT COULD SERIOUSLY DAMAGE THE VALUE OF YOUR COMPANY

The linchpin of Icahn’s platform for his nominees — his “Plan A”— continues to be a risky public sale process for your company. This public sale process might provide Icahn with liquidity, but has the potential for significant value destruction and could derail the business and financial momentum that Mentor Graphics currently enjoys. It is clear that Icahn is simply continuing to ignore the regulatory obstacles and commercial risks to any transaction with Synopsys or Cadence, despite knowing that the analysis we recently performed shows that there are serious regulatory risks to any transaction with these two companies. He also continues to ignore the destruction of value through loss of customers and employees from any failed process to sell the company.

Icahn is now attempting to piggyback on the Board’s focus and progress on further expense reduction and share repurchase through his so-called “Plan B,” which calls for further expense reduction and share repurchase. The truth is that there is simply nothing new in Icahn’s “Plan B” that Mentor Graphics is not already doing and therefore no need to elect Icahn’s nominees.

Your Vote is Important and We Urge You to Vote FOR Your Board’s Nominees TODAY by Telephone, Internet or by Signing, Dating and Returning the WHITE Proxy Card.

On behalf of your Board of Directors, we appreciate your support and continued interest in Mentor Graphics. If you have any questions please contact MacKenzie Partners, Inc., which is assisting us in connection with this year’s Annual Meeting, at (212) 929−5500 or TOLL−FREE at (800) 322−2885.

Sincerely,

/s/

Walden C. Rhines

Chairman of the Board and Chief Executive Officer

About Mentor Graphics

Mentor Graphics Corporation (NASDAQ: MENT) is a world leader in electronic hardware and software design solutions, providing products, consulting services and award-winning support for the world’s most successful electronic, semiconductor and systems companies. Established in 1981, the company reported revenues over the last 12 months of about $915 million. Corporate headquarters are located at 8005 S.W. Boeckman Road, Wilsonville, Oregon 97070-7777. World Wide Web site: http://www.mentor.com/.

Important Information

On March 31, 2011, the company filed a definitive proxy statement with the Securities and Exchange Commission (the “SEC”) in connection with the company’s upcoming 2011 annual meeting of shareholders. Shareholders are advised to read the company’s definitive proxy statement and any other relevant documents filed by the company with the SEC, before making any voting or investment decision because they contain important information. The definitive proxy statement is, and any other relevant documents and other material filed with the SEC concerning the company will be, when filed, available free of charge at http://www.sec.gov and http://www.mentor.com/company/investor_relations. In addition, copies of the proxy materials may be requested from the company’s proxy solicitor, MacKenzie Partners, Inc., by telephone at 1-800-322-2885 or by email at Email Contact.

Forward-Looking Statements

Statements in this material regarding the company’s outlook for future periods constitute “forward-looking” statements based on current expectations within the meaning of the Securities Exchange Act of 1934. Such forward-looking statements involve known and unknown risks, uncertainties and other factors that may cause the actual results, performance or achievements of the company or industry results to be materially different from any results, performance or achievements expressed or implied by such forward-looking statements. Such factors include, among others, the following: (i) weakness or recession in the US, EU, Japan or other economies; (ii) the company’s ability to successfully offer products and services that compete in the highly competitive EDA industry; (iii) product bundling or discounting of products and services by competitors, which could force the company to lower its prices or offer other more favorable terms to customers; (iv) possible delayed or canceled customer orders, a loss of key personnel or other consequences resulting from the business disruption and uncertainty of prolonged proxy fights, offers to purchase the company’s securities or other actions of activist shareholders; (v) effects of the increasing volatility of foreign currency fluctuations on the company’s business and operating results; (vi) changes in accounting or reporting rules or interpretations; (vii) the impact of tax audits by the IRS or other taxing authorities, or changes in the tax laws, regulations or enforcement practices where the company does business; (viii) effects of unanticipated shifts in product mix on gross margin; and (ix) effects of customer seasonal purchasing patterns and the timing of significant orders, which may negatively or positively impact the company’s quarterly results of operations, all as may be discussed in more detail under the heading “Risk Factors” in the company’s most recent Form 10-K or Form 10-Q. Given these uncertainties, prospective investors are cautioned not to place undue reliance on such forward-looking statements. The company disclaims any obligation to update any such factors or to publicly announce the results of any revisions to any of the forward-looking statements to reflect future events or developments.