WASHINGTON, D.C., June 19, 2006 - Cogent Communications Group, Inc. (NASDAQ: CCOI), one of the largest Internet service providers in the world in terms of traffic carried on its network, announced today that it is expanding its presence into several new, metropolitan markets with Cogent's On-Net dedicated Internet access service. Cogent is newly providing its high quality, low priced Internet service to Phoenix, Arizona; Buffalo, New York; and Milan, Italy and will be rolling out service to Zurich, Switzerland and Montreal, Canada within 60 days. New customers in these markets will receive one free month of Internet service. Existing customers located outside of these markets but interested in purchasing service in these new markets are also eligible for this offer.

Furthermore, Cogent has acquired an additional 10 Gigabits of transatlantic fiber-optic network capacity, bringing its total undersea capacity to 50 Gigabits across 5 diverse routes.

Cogent's offer of a risk-free month of complimentary Internet service is available to any new or existing customer that signs up with Cogent in these markets. Customers can cancel for any reason during the first 30 days if unsatisfied with Cogent's Internet service. Cogent is also extending this offer to new customers in Copenhagen, Denmark and Stockholm, Sweden, new markets that Cogent announced several months ago. For more details, see the "Special Promotions" link on Cogent's homepage at www.cogentco.com.

"Cogent takes a very judicious approach to market expansion," said Dave Schaeffer, CEO of Cogent Communications. "We invest time researching the new market, looking at available dark fiber providers, fiber routes, building profiles and their proximity to dark fiber. Most importantly, we evaluate the tenant profiles and opportunities within the buildings in those markets. Cogent will not enter a new market unless we are confident it will quickly make a positive contribution to Cogent's bottom line."

With the new markets announced today, Cogent's footprint now includes over 95 markets in 14 countries where Cogent offers dedicated Internet service.

About Cogent Communications

Cogent Communications (NASDAQ: CCOI) is a multinational, Tier 1 ISP recently ranked by Ovum-RHK as the largest provider of Ethernet services in the United States. Cogent specializes in providing businesses with high speed Internet access and point-to-point transport services. Cogent's facilities-based, all-optical IP network backbone spans 14 countries and provides IP services in over 95 markets located in North America and Europe.

Since Cogent's inception, Cogent has unleashed the benefits of IP technology, building one of the largest and highest capacity IP networks in existence. This network enables Cogent to offer large bandwidth connections at highly competitive prices. Network ownership also enables Cogent to offer superior customer support through end-to-end control of service delivery and network monitoring.

Cogent Communications is headquartered at 1015 31st Street, NW, Washington, D.C. 20007. For more information, visit www.cogentco.com. Cogent Communications can be reached in the United States at (202) 295-4200 or via email at This email address is being protected from spambots. You need JavaScript enabled to view it..

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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.

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