MCI Canada Adds Traditional Long Distance Voice Services to Data and Internet Communications Portfolio

Addition of Long Distance, Toll-Free and Calling Card Services
Complement MCI Canada's Existing IP and Data Solutions

TORONTO, Ont., June 1, 2004 - MCI Canada, a wholly-owned subsidiary of MCI (MCIA.PK), today announced the expansion of its suite of data, Internet and voice over Internet Protocol (VoIP) business communications solutions with the addition of traditional long distance voice, toll-free and calling card services delivered via the public switched telephone network (PSTN). Available immediately, MCI's Voice Solutions offer a new opportunity for companies to reliably maximize the value of their domestic and international voice and data communications investment while leveraging the simplicity and convenience of a single-source service provider.

"Regardless of whether a customer uses PSTN- or VoIP-based calling for their business, MCI has the answer for their essential inbound and outbound long distance requirements," said Sam Mazzotta, MCI Canada's director of products. "Both are supported by MCI's global network infrastructure with superior customer care, backed by service level agreements guaranteeing performance and reliability. Combined with our advanced data and Internet products, these new services make MCI the one-stop shop for Canadian business communications."

• Long Distance: For Canadian companies with national or international offices, customers, partners or suppliers, MCI provides PSTN and VoIP long distance voice services at competitive domestic and international rates, helping customers to control telecom costs. Its extended reach enables companies to contact clients and colleagues in practically any country. Companies receive monthly printed invoices showing a summary of all charges, and they have access to detailed information for each call placed including date, time, location, duration and cost.
• Toll Free: MCI's Toll Free services enable a company to receive inbound calls that originate outside of its local calling area - within Canada or from international locations - making its services or support more accessible to its customers. Businesses rely on MCI Toll Free to boost productivity, increase customer satisfaction and reduce their telecom and staffing costs.

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• Calling Card: With MCI's Hemispheres Calling Card, traveling business professionals can keep in touch from anywhere in Canada or around the world. With MCI's extensive worldwide access, mobile and traveling workers can use a single calling card in any country where they do business. MCI's Hemispheres Calling Card offers competitive country-to-country calling card rates, with no per-call surcharges. Cardholders using a standard touch-tone telephone simply dial a country-specific access number to reach a voice prompt or to get assistance from a multilingual operator who will connect the call.

Businesses that rely on MCI Voice Solutions receive other benefits as well, including:

Preparation for the Future: Whether companies are continuing to rely on traditional PSTN or preparing for the future with VoIP, they can rely on MCI's Voice Solutions to keep them ready for the future.

Unsurpassed Reach and Reliability: MCI owns, operates, monitors and maintains one of the largest communications networks in the world with network facilities throughout North America, Latin America, Europe, Africa, and the Asia-Pacific region, reaching more than 140 countries and 2,800 cities. MCI operates the industry's most expansive global IP backbone (based on more than 4,500 company-owned points of presence) and the most robust set of converged communications services in the industry, including integrated voice, data, and Internet services.

Customer Service: MCI's customers can rely on unmatched technical resources, people, and experience. MCI continually monitors the status of the network and offers expert customer support 24 hours a day, seven days a week.

"The vast majority of organizations, both public and private, have now implemented some type of network infrastructure that utilizes the Internet Protocol to transport and download files," said Mazzotta. "IP is positioned to become the preferred method for more business applications, Web services, and voice and video communications. As the first commercial Internet service provider in Canada, MCI is uniquely qualified to serve companies interested in pursuing these next-generation IP-based services that will increase the productivity and efficiency of their business operations."

About MCI
MCI, Inc. (MCIA.PK) is a leading global communications provider, delivering innovative, cost-effective advanced communications connectivity to businesses, governments and consumers. With the industry's most expansive global IP backbone, based on the number of company-owned points-of-presence, and wholly-owned data networks, MCI develops the converged communications products and services that are the foundation for commerce and communications in today's markets. For more information, go to www.mci.com.

Media Contact:
Deborah Brown
MCI Canada
Tel: (416) 216-5196

Investors Contact:
Susan Watson
MCI Investor Relations
Tel: (877) 624-9266