Exhibit 99.1

Cogent Communications Reports First Quarter 2011 Results

Financial and Business Highlights

·                  Service revenue for Q1 2011 of $73.5 million — an increase of 5.8% from $69.5 million for Q4 2010 and an increase of 17.0% from $62.8 million for Q1 2010

·                  Foreign exchange positively impacts revenue growth from Q4 2010 to Q1 2011 by $0.2 million and positively impacts revenue growth from Q1 2010 to Q1 2011 by $0.1 million

·                  Traffic growth of 18% from Q4 2010 to Q1 2011 and traffic growth of 39% from Q1 2010 to Q1 2011

·                  EBITDA, as adjusted, of $24.2 million for Q1 2011 - an increase of 7.4% from $22.6 million for Q4 2010 and an increase of 38.5% from $17.5 million for Q1 2010

·                  EBITDA, as adjusted, margin was 33.0% for Q1 2011, 32.5% for Q4 2010 and 27.9% for Q1 2010

·                  26,145 customer connections on the Cogent network at the end of Q1 2011 - an increase of 4.4% from 25,046 customer connections at the end of Q4 2010 and an increase of 17.6% from 22,237 customer connections at the end of Q1 2010

·                  1,609 on-net buildings on the Cogent network at the end of Q1 2011 - an increase of 30 on-net buildings and 1.9% from 1,579 on-net buildings at the end of Q4 2010 and an increase of 134 on-net buildings and 9.1% from 1,475 on-net buildings at the end of Q1 2010

·                  Gross profit margin, as adjusted, was 56.9% for Q1 2011, 55.5% for Q4 2010 and 55.3% for Q1 2010

·                  Raised $170.5 million of net proceeds from the issuance of Senior Secured Notes

[WASHINGTON, D.C. May 5, 2011] Cogent Communications Group, Inc. (NASDAQ: CCOI) today announced service revenue of $73.5 million for the three months ended March 31, 2011, an increase of 5.8% over $69.5 million for the three months ended December 30, 2010 and an increase of 17.0% over $62.8 million for the three months ended March 31, 2010.

On-net revenue was $56.8 million for the three months ended March 31, 2011, an increase of 5.9% over $53.6 million for the three months ended December 31, 2010 and an increase of

14.4% over $49.6 million for the three months ended March 31, 2010. On-net service is provided to customers located in buildings that are physically connected to Cogent’s network by Cogent facilities.

Off-net revenue was $16.0 million for the three months ended March 31, 2011, an increase of 5.6% over $15.1 million for the three months ended December 31, 2010 and an increase of 29.5% over $12.3 million for the three months ended March 31, 2010. Off-net customers are located in buildings directly connected to Cogent’s network using other carriers’ facilities and services to provide the last mile portion of the link from the customers’ premises to Cogent’s network.

Non-core revenue was $0.7 million for the three months ended March 31, 2011, $0.8 million for the three months ended December 31, 2010 and $0.8 million for the three months ended March 31, 2010.  Non-core services are legacy services, which Cogent acquired and continues to support but does not actively sell.

Gross profit, excluding equity-based compensation expense, increased 8.6% to $41.8 million for the three months ended March 31, 2011 from $38.5 million for the three months ended December 31, 2010 and increased 20.5% from $34.7 million for the three months ended March 31, 2010.  Gross profit margin, excluding equity-based compensation expense, was 56.9% for the three months ended March 31, 2011, 55.5% for the three months ended December 31, 2010, and 55.3% for the three months ended March 31, 2010.

Earnings before interest, taxes, depreciation and amortization (EBITDA), as adjusted, increased 7.4% to $24.2 million for the three months ended March 31, 2011 from $22.6 million for the three months ended December 31, 2010 and increased 38.5% from $17.5 million for the three months ended March 31, 2010.  EBITDA, as adjusted, margin was 33.0% for the three months ended March 31, 2011, 32.5% for the three months ended December 31, 2010, and 27.9% for the three months ended March 31, 2010.

Basic and diluted net income (loss) per share was $(0.01) for the three months ended March 31, 2011, $0.06 for the three months ended December 31, 2010 and $(0.01) for the three months ended March 31, 2010.

Total customer connections increased 4.4% to 26,145 as of March 31, 2011 from 25,046 as of December 31, 2010 and increased 17.6% from 22,237 as of March 31, 2010. On-net customer connections increased 4.8% to 21,878 as of March 31, 2011 from 20,872 as of December 31, 2010 and increased 20.9% from 18,097 as of March 31, 2010.  Off-net customer connections were 3,642 as of March 31, 2011, 3,526 as of December 31, 2010 and 3,310 as of March 31, 2010.  Non-core customer connections were 625 as of March 31, 2011, 648 as of December 31, 2010 and 830 as of March 31, 2010.

The number of on-net buildings increased by 30 on-net buildings to 1,609 on-net buildings as of March 31, 2011 from 1,579 on-net buildings as of December 31, 2010, and increased by 134 on-net buildings from 1,475 on-net buildings as of March 31, 2010.

Conference Call and Website Information

Cogent will host a conference call with financial analysts at 8:30 a.m. (ET) on May 5, 2011 to discuss Cogent’s operating results for the first quarter of 2011 and Cogent’s expectations for full year 2011.  Investors and other interested parties may access a live audio webcast of the earnings call under “Events” at the Investor Relations section of Cogent’s website at www.cogentco.com/events.  A replay of the webcast, together with the press release, will be available on the website following the earnings call.

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 provides IP services in over 160 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 info@cogentco.com.

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COGENT COMMUNICATIONS GROUP, INC., AND SUBSIDIARIES

Summary of Financial and Operational Results

(1)          Consists of legacy services of companies whose assets or businesses were acquired by Cogent, primarily including voice services (only provided in Toronto, Canada).

(2)         Excludes equity-based compensation expense of $47, $95, $104, $124 and $140 in the three months ended March 31, 2010, June 30, 2010, September 30, 2010, December 31, 2010 and March 31, 2011, respectively.

(3)         Excludes equity-based compensation expense of $1,118, $1,701, $1,695, $1,753 and $1,956 in the three months ended March 31, 2010, June 30, 2010, September 30, 2010, December 31, 2010 and March 31, 2011, respectively.

(4)         See schedule of non-GAAP metrics below for definition and reconciliation to GAAP measures. EBITDA, as adjusted, includes net gains from asset related transactions of $185, $4, $50, $25 and $2 in the three months ended March 31, 2010, June 30, 2010, September 30, 2010, December 31, 2010 and March 31, 2011, respectively.

Schedule of Non-GAAP Measures

EBITDA and EBITDA, as adjusted

EBITDA represents net (loss) income before income taxes, net interest expense, equity-based compensation expense and depreciation and amortization. Management believes the most directly comparable measure to EBITDA calculated in accordance with generally accepted accounting principles in the United States, or GAAP, is cash flows provided by operating activities.

EBITDA, as adjusted, represents EBITDA plus gains on asset related transactions. The Company believes EBITDA, as adjusted, is a useful measure of its ability to service debt, fund capital expenditures and expand its business.  EBITDA, as adjusted, is an integral part of the internal reporting and planning system used by management as a supplement to GAAP financial information. The Company also believes that EBITDA is a frequently used measure by securities analysts, investors, and other interested parties in their evaluation of issuers.

EBITDA and EBITDA, as adjusted, are not recognized terms under GAAP and accordingly, should not be viewed in isolation or as a substitute for the analysis of results as reported under GAAP, but rather as a supplemental measure to GAAP. For example, EBITDA is not intended to reflect the Company’s free cash flow, as it does not consider certain current or future cash requirements, such as capital expenditures, contractual commitments, and changes in working capital needs, interest expenses and debt service requirements. The Company’s calculations of EBITDA and EBITDA, as adjusted, may also differ from the calculation of EBITDA and EBITDA, as adjusted, by its competitors and other companies and as such, its utility as a comparative measure is limited.

COGENT COMMUNICATIONS GROUP, INC., AND SUBSIDIARIES

EBITDA, as adjusted, is reconciled to cash flows provided by operating activities in the table below.

Impact of foreign currencies on sequential quarterly service revenue

(1)         Service revenue as adjusted is determined by translating the service revenue for the three months ended March 31, 2011 at the average foreign currency exchange rates for the three months ended December 31, 2010. The Company believes that disclosing quarterly revenue growth without the impact of foreign currencies on service revenue is a useful measure of revenue growth. Service revenue, as adjusted, is an integral part of the internal reporting and planning system used by management as a supplement to GAAP financial information.

Cogent’s SEC filings are available online via the Investor Relations section of www.cogentco.com or on the Securities and Exchange Commission’s website at www.sec.gov.

COGENT COMMUNICATIONS GROUP, INC., AND SUBSIDIARIES

CONDENSED CONSOLIDATED BALANCE SHEETS

AS OF MARCH 31, 2011 AND DECEMBER 31, 2010
(IN THOUSANDS, EXCEPT SHARE DATA)

COGENT COMMUNICATIONS GROUP, INC., AND SUBSIDIARIES

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS

FOR THE THREE MONTHS ENDED MARCH 31, 2011 AND MARCH 31, 2010
(IN THOUSANDS, EXCEPT SHARE AND PER SHARE AMOUNTS)

COGENT COMMUNICATIONS GROUP, INC., AND SUBSIDIARIES

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS

FOR THE THREE MONTHS ENDED MARCH 31, 2011 AND MARCH 31, 2010
(IN THOUSANDS)

Except for historical information and discussion contained herein, statements contained in this release constitute forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995.  Such statements include, but are not limited to statements identified by words such as “believes,” “expects,” “anticipates,” “estimates,” “intends,” “plans,” “targets,” “projects” and similar expressions.  The statements in this release are based upon the current beliefs and expectations of Cogent’s management and are subject to significant risks and uncertainties.  Actual results may differ from those set forth in the forward-looking statements.  Numerous factors could cause or contribute to such differences, including future economic instability in the global economy or a contraction of the capital markets which could affect spending on Internet services and our ability to engage in financing activities; the impact of changing foreign exchange rates (in particular the Euro to USD and Canadian dollar to USD exchange rates) on the translation of our non-USD denominated revenues, expenses, assets and liabilities; legal and operational difficulties in new markets; the imposition of a requirement that we contribute to the Universal Service Fund; changes in government policy and/or regulation, including net neutrality rules  by the United States Federal Communications Commission and in the area of data protection; increasing competition leading to lower prices for our services; our ability to attract new customers and to increase and maintain the volume of traffic on our network; the ability to maintain our Internet peering arrangements on favorable terms; our reliance on an equipment vendor, Cisco Systems Inc., and the potential for hardware or software problems associated with such equipment; the dependence of our network on the quality and dependability of third-party fiber providers; our ability to retain certain customers that comprise a significant portion of our revenue base; the management of network failures and/or disruptions; and outcomes in litigation as well as other risks discussed from time to time in our filings with the Securities and Exchange Commission, including, without limitation, our annual report on Form 10-K for the fiscal year ended December 31, 2010 and our quarterly report on Form 10-Q for the quarter ended March 31, 2011, to be filed with the Securities and Exchange Commission. Cogent undertakes no duty to update any forward-looking statement or any information contained in this press release or in other public disclosures at any time.

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