Mittal Steel Co. NV and International Steel Group Inc. announced that the registration statement on Form F-4 filed by Mittal Steel with the Securities and Exchange Commission in connection with the proposed merger involving ISG and Mittal Steel has been declared effective as of March 11, 2005.

The definitive proxy statement/prospectus contained in the registration statement, together with a form of proxy, will be first mailed to ISG stockholders followed by a form of election (under separate cover). The form of election can be used to elect cash, Mittal Steel class A common shares or a combination of both in respect of stockholders’ ISG shares, as provided in the merger agreement. The form of election will also be posted on ISG's website.

ISG and Mittal Steel will each hold special meetings of their shareholders on April 12, 2005, to vote on the proposed merger. ISG stockholders of record at the close of business on March 14, 2005 will be entitled to vote on the proposal at the special meeting of ISG stockholders, which will be held at 10:00 a.m. in New York, N.Y.. The special meeting of Mittal Steel shareholders will be held at 3:00 p.m. in Rotterdam, The Netherlands.

The merger is subject to approval by the shareholders of both ISG and Mittal Steel and the satisfaction of other customary closing conditions.

Mittal Steel Co. is the world's most global steel company. Formed from the combination of Ispat International NV and LNM Holdings NV, the company has operations in fourteen countries, on four continents. Mittal Steel encompasses all aspects of modern steelmaking, to produce a comprehensive portfolio of both flat and long steel products to meet a wide range of customer needs. It serves all the major steel consuming sectors, including automotive, appliance, machinery and construction.

International Steel Group Inc. (ISG) is one of the largest steel producers in North America. It ships a variety of steel products from 13 major steel producing and finishing facilities in eight states, including hot-rolled, cold-rolled and coated sheets, tin mill products, carbon and alloy plates, rail products and semi-finished shapes to serve the automotive, construction, pipe and tube, appliance, container and machinery markets.