Cogent Extends Network Presence in Europe

AMSTERDAM, November 30, 2005 - Cogent Communications Group, Inc. (AMEX: COI), a multinational Tier 1 Internet service provider, announced its planned expansion to provide Internet access and transport services in Stockholm, Sweden. Cogent will make an official announcement at its customer event to be held at the U.S. General Consulate's building in Amsterdam on November 30th, 2005.

"Cogent is responding to customer demand and multiple requests from businesses looking to bring Cogent's quality Internet service and pricing to Sweden," said Dave Schaeffer, CEO of Cogent Communications. "We are looking forward to launching service in Stockholm in the very near future and want to take this opportunity while in Amsterdam to personally thank our loyal customers for their business today and continued future support as we expand our presence throughout Europe."

Stefan Arbia, Cogent's Country Manager for the Benelux region, will host the event and introduce Cogent's CEO Dave Schaeffer, as well as other senior executives from Cogent, to an influential group including consulate officials and telecommunications industry executives. The event will provide an excellent forum to network and discuss further opportunities and trends in the Internet marketplace.

Cogent's has steadily increased the amount of traffic and number of customers on its network, located in Europe and North America. Cogent reported its network traffic grew 30% in the 3rd quarter of 2005. Compounded annual growth in traffic for 2005 is roughly 170%. Cogent estimates that it carries approximately 12% of the world's Internet traffic based on comparisons of its data with that of third parties that publish total global Internet traffic statistics. Cogent has been named the largest Ethernet Internet service provider in the United States by Ovum-RHK and continues to demonstrate its leadership position within the telecom industry both in Europe and the United States.

About Cogent Communications

Cogent Communications (AMEX: COI) is the number one provider of Ethernet services in the United States as ranked by Ovum-RHK and is one of the largest ISPs in the world. Its facilities based, all-optical network delivers ultra-high speed Internet access and transport services to businesses and service providers in major metropolitan areas. Cogent offers services across its 46,600 Km IP network spanning 12 countries located in North America and Europe.

The combination of technology, IP network architecture and unique business model has combined to help make Cogent one of the most popular Tier 1 providers of reliable, cost-effective Internet service in the industry. Cogent offers several focused services that complement its On-Net Internet access service including dedicated Off-Net (E1, E3) Internet service, colocation services in 28 colocation facilities across North America and Europe, and Layer 2 Point-to-Point services in every On-Net market.

Cogent Communications is headquartered at 1015 31st Street, NW, Washington, D.C. 20007. For more information, visit Cogent Communications can be reached in the United States at (202) 295-4200 or via email at Cette adresse e-mail est protégée contre les robots spammeurs. Vous devez activer le JavaScript pour la visualiser..

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Information in this release may involve expectations, beliefs, plans, intentions or strategies regarding the future. These forward-looking statements involve risks and uncertainties. All forward-looking statements included in this release are based upon information available to Cogent Communications Group, Inc. as of the date of the release, and we assume no obligation to update any such forward-looking statement. The statements in this release are not guarantees of future performance and actual results could differ materially from our current expectations. Numerous factors could cause or contribute to such differences. Some of the factors and risks associated with our business are discussed in Cogent's registration statements filed with the Securities and Exchange Commission and in its other reports filed from time to time with the SEC.