ROCHESTER, NY – September 14, 2005 — Mpower Holding Corporation (AMEX:MPE), the parent company of Mpower Communications Corp., a leading provider of data and voice services to retail and wholesale business customers, announced today that it will be presenting at the Jefferies 3rd Annual Communications & Media Conference on Monday, September 19, 2005 from 10:20 to 11:00 a.m. EST.

Mpower Communications Chairman and Chief Executive Officer Rolla P. Huff and Chief Financial Officer Gregg Clevenger, will present an overview of the company, its growth strategies and position within the telecommunications industry.

The conference is being held at the Mandarin Oriental Hotel, 80 Columbus Circle at 60 th Street in New York City.

Mpower Communications (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.