ROCHESTER, NY—February 4, 2004—Mpower Holding Corporation (AMEX:MPE), the parent company of Mpower Communications Corp, a leading provider of broadband Internet, local and long distance voice services, today announced it has filed a universal shelf registration statement on Form S-3 with the Securities and Exchange Commission seeking to register $250 million of new securities, which could include shares of its common stock, preferred stock, warrants to purchase common stock or debt securities.

Mpower does not currently have any plans to raise capital through the issuance of capital stock and more particularly, has no plans whatsoever at this time to increase leverage through the issuance of debt securities. However, the shelf may be utilized in the future to enter into strategic transactions or for general corporate purposes, which may include acquisition transactions and other growth activities. The amounts, prices and other terms of any such new securities will be determined at the time of particular transactions.

When available, a prospectus meeting the requirements of Section 10 of the Securities Act may be obtained from Mpower Holding Corporation Investor Relations department by calling 585-218-6550 or via an email to invest@mpowercom.com.

A registration statement relating to these securities has been filed with the SEC but has not yet become effective. These securities may not be sold nor may offers to buy be accepted prior to the time the registration statement becomes effective. This news release shall not constitute an offer to sell or the solicitation of an offer to buy nor shall there be any sale of these securities in any State in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such State.

About Mpower Holding Corporation
Mpower Holding Corporation (AMEX:MPE) is the parent company of Mpower Communications, a leading facilities-based broadband communications provider offering a full range of data, telephony, Internet access and Web hosting services for small and medium-size business customers. Further information about the company can be found at www.mpowercom.com.

Forward-Looking Statements
Under the safe harbor provisions of the Private Securities Litigation Reform Act of 1995, Mpower Holding Corporation cautions investors that certain statements contained in this press release that state management's intentions, hopes, beliefs, expectations or predictions of the future are forward-looking statements. Management wishes to caution the reader these forward-looking statements are not historical facts and are only estimates or predictions. Actual results may differ materially from those projected as a result of risks and uncertainties including, but not limited to, receipt of all remaining payments from the previously announced asset sales, future sales growth, market acceptance of our product offerings, our ability to secure adequate financing or equity capital to fund our operations, network expansion, our ability to manage growth and maintain a high level of customer service, the performance of our network and equipment, our ability to enter into strategic alliances or transactions, the cooperation of incumbent local exchange carriers in provisioning lines and interconnecting our equipment, regulatory approval processes, changes in technology, price competition and other market conditions and risks detailed from time to time in our Securities and Exchange Commission filings. The company undertakes no obligation to update publicly any forward-looking statements, whether as a result of future events, new information, or otherwise.