ROCHESTER, NY -- AUGUST 13, 2004 -- Mpower Communications Corp., a leading provider of broadband Internet access and telephone services to business customers, applauded yesterday’s revised proposed decision by the Administrative Law Judge (ALJ), that if adopted by the California Public Utilities Commission, would establish new unbundled network element rates for competitive access to SBC’s California network.

“The proposed new rate structure would enable Mpower to continue to grow in California by leveraging our investment in owning and operating our facilities-based network,” commented Mpower Communications Chairman and Chief Executive Officer Rolla P. Huff. “ This revised proposal is a marked improvement over the previous proposed decision by the ALJ and, if adopted, would still significantly lower DS-1 loop rates while dramatically cutting the proposed increases in DSO rates.”

About Mpower Holding Corporation

Mpower Holding Corporation (AMEX:MPE) is a facilities-based broadband communications provider established in 1996. Mpower offers 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, certain statements contained in this press release regarding our and/or management’s intentions, hopes, beliefs, expectations or predictions of the future are forward-looking statements. 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, sales growth, changes in federal or state telecommunications regulations, market acceptance of our product and service offerings, the liquidity of our common stock, our ability to secure adequate financing or equity capital to fund our operations and 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, the effect of regulatory decisions on our access charges and operating costs, changes in technology, price competition and other market conditions and risks detailed from time to time in our filings with the Securities and Exchange Commission. We undertake no obligation to update publicly any forward-looking statements, whether as a result of future events, new information, or otherwise.