Martin Marietta Materials
May 24, 2005

Martin Marietta Materials, Inc. Declares Regular Cash Dividend Of 20 Cents Per Share

RALEIGH, North Carolina (May 24, 2005) - Stephen P. Zelnak, Jr., Chairman and Chief Executive Officer of Martin Marietta Materials, Inc. (NYSE:MLM), today announced that the Board of Directors has declared a regular quarterly cash dividend of $0.20 per share on the Corporation's common stock. This dividend, which represents a cash dividend of $0.80 per share on an annualized basis, is payable June 30, 2005, to shareholders of record at the close of business on June 1, 2005.

Martin Marietta is the nation's second largest producer of construction aggregates, a leading producer of magnesia-based chemical products and is developing structural composites products for use in a wide variety of industries.