WASHINGTON, D.C., June 2, 2006 - Cogent Communications Group, Inc. (NASDAQ: CCOI) announced today that the underwritten public offering of 9.0 million shares of its common stock has been priced at $9.00 per share. The 9.0 million shares being sold in the offering consist of 4.0 million newly-issued shares of common stock sold by Cogent and 5.0 million shares of common stock sold by selling stockholders. The sale of 4.0 million shares by Cogent will result in gross proceeds, before underwriting discounts and offering expenses, of $36.0 million. Lehman Brothers and Bear, Stearns & Co. Inc. are acting as joint book-running managers for the offering, Thomas Weisel Partners LLC is acting as joint lead manager and Wachovia Securities and Friedman Billings Ramsey are acting as co-managers.

The offering is expected to close on June 7, 2006, subject to customary closing conditions. The underwriters of the offering have a 30-day option to purchase an additional 1.35 million shares of common stock from Cogent, Dave Schaeffer, Cogent's Chairman and CEO, and certain selling stockholders.

Copies of the final prospectus supplement and related base prospectus for the offering, when available, may be obtained by contacting:

Lehman Brothers Inc.

c/o ADP Financial Services

Prospectus Fulfillment

1155 Long Island Avenue

Edgewood, NY 11717

Fax: (631) 254-7268

Email: Diese E-Mail-Adresse ist vor Spambots geschützt! Zur Anzeige muss JavaScript eingeschaltet sein!

OR

Bear, Stearns & Co. Inc.

c/o Prospectus Department

383 Madison Avenue

New York, NY 10179

Phone: (866) 803-9204

This press release shall not constitute an offer to sell or a solicitation of an offer to buy common stock nor shall there be any sale of such securities in any state or jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state or jurisdiction.

About Cogent Communications

Cogent Communications (NASDAQ: CCOI) is a multinational, Tier 1 facilities-based ISP. 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.

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 Diese E-Mail-Adresse ist vor Spambots geschützt! Zur Anzeige muss JavaScript eingeschaltet sein!.

# # #

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.

###