WASHINGTON, D.C., October 19, 2006 - Cogent Communications, Inc., one of the largest carriers of Internet traffic in the world, today announced that Cogent was ranked as the 56th fastest growing company in North America by Deloitte's 2006 Technology Fast 500 Program. Cogent made the list based on average percentage revenue growth of 4,380 percent over five years from 2001 to 2005. The average growth rate of all 500 companies named was 2,147 percent.

"To rank on Deloitte's Technology Fast 500, companies must have phenomenal revenue growth over five years. Cogent has proven to be one of the fast-growth success stories in North America, and we applaud their dedication to making their vision a reality," said Tony Kern, deputy managing principal of Deloitte's Technology, Media & Telecommunications industry practice.

"Cogent's remarkable growth rate can be attributed to the clarity, focus and determination that our employees put into delivering the highest quality Internet service at the lowest prices in the industry," said Dave Schaeffer, CEO of Cogent. "It is doubly amazing that we have been able to achieve this type of growth based predominantly on customer word-of-mouth. This underscores the unprecedented value that Cogent delivers."

About Cogent Communications

Cogent Communications Group, Inc. (NASDAQ: CCOI) is a multinational, Tier 1 facilities-based ISP 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 approximately 90 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 Cette adresse e-mail est protégée contre les robots spammeurs. Vous devez activer le JavaScript pour la visualiser..

About Deloitte

Deloitte refers to one or more of Deloitte Touche Tohmatsu, a Swiss Verein, its member firms, and their respective subsidiaries and affiliates. Deloitte Touche Tohmatsu is an organization of member firms around the world devoted to excellence in providing professional services and advice, focused on client service through a global strategy executed locally in nearly 150 countries. With access to the deep intellectual capital of approximately 135,000 people worldwide, Deloitte delivers services in four professional areas—audit, tax, consulting and financial advisory services—and serves more than one-half of the world's largest companies, as well as large national enterprises, public institutions, locally important clients, and successful, fast-growing global growth companies. Services are not provided by the Deloitte Touche Tohmatsu Verein, and, for regulatory and other reasons, certain member firms do not provide services in all four professional areas.

As a Swiss Verein (association), neither Deloitte Touche Tohmatsu nor any of its member firms has any liability for each other's acts or omissions. Each of the member firms is a separate and independent legal entity operating under the names "Deloitte", "Deloitte & Touche", "Deloitte Touche Tohmatsu", or other related names.

In the United States, Deloitte & Touche USA LLP is the member firm of Deloitte Touche Tohmatsu, and services are provided by the subsidiaries of Deloitte & Touche USA LLP (Deloitte & Touche LLP, Deloitte Consulting LLP, Deloitte Financial Advisory Services LLP, Deloitte Tax LLP, and their subsidiaries), and not by Deloitte & Touche USA LLP. The subsidiaries of the U.S. member firm are among the nation's leading professional services firms, providing audit, tax, consulting, and financial advisory services through nearly 40,000 people in more than 90 cities. Known as an employer of choice for innovative human resources programs, it is dedicated to helping their clients and their people excel. For more information, please visit the U.S. member firm's Web site at www.deloitte.com/us.

# # #

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.

###