ATHENAHEALTH, INC. REPORTS FIRST-QUARTER 2008 RESULTS

— 36% Revenue Growth, Compared to Same Quarter Last Year — Non-GAAP Adjusted Quarterly Net Income of $3.1 Million or $0.09 Per Share — 13% Adjusted EBITDA Margin, Compared to 3% in Same Quarter Last Year

WATERTOWN, Mass. (May 06, 2008) – athenahealth, Inc. (Nasdaq: ATHN), a leading provider of internet-based business services for physician practices, today announced financial results for the first-quarter of 2008. The Company also plans to discuss a significant new client contract on today’s conference call.

Total revenue for the three months ended March 31, 2008 was $29.8 million, compared to $21.9 million for the same period last year, an increase of 36%.

“In the first quarter we increased our revenue growth rate as we added to the size and scope of our national physician network,” said Jonathan Bush, Chairman and Chief Executive Officer of athenahealth. “Our financial performance is a credit to the loyalty and hard work of our clients and the effectiveness of our software-enabled services.”

For the three months ended March 31, 2008, the Company’s Non-GAAP Adjusted EBITDA of $4.0 million was 13% of revenue, compared to a Non-GAAP Adjusted EBITDA of $0.7 million for the same period last year. Non-GAAP Adjusted Net Income in the quarter was $3.1 million, compared to a Non-GAAP Adjusted net loss of $1.5 million in the same period last year. GAAP net income for the quarter was $1.8 million, compared to a GAAP Net Loss of $2.7 million in the same period last year.

“In our history, the first quarter often involves margin compression due to costs at the start of the year and lower seasonal physician collections, so we were quite pleased to see strength both in revenue growth and in margin expansion this quarter,” said Carl Byers, Chief Financial Officer.

Key metrics and milestones in the first-quarter of 2008 included the following:

— $797 million in cash collections posted to client accounts in the first-quarter of 2008, compared to $606 million in the same quarter of 2007

— 9,810 active physicians live in the first-quarter of 2008, compared to 7,639 in the same quarter of last year

— 12,723 active medical providers live in first-quarter of 2008, compared to 9,827 in the same quarter of last year

— Completion of the Company’s purchase of an operating center campus in Belfast, Maine for $6.1 million

As of March 31, 2008, the Company had cash and short-term investments of $66.5 million and short- and long-term debt of $1.7 million.

A reconciliation of the Company’s financial results determined in accordance with United States generally accepted accounting principles (GAAP) to certain non-GAAP financial measures has been provided in the financial statement tables included in this press release. An explanation of these measures is also included below under the heading “Explanation of Non-GAAP Financial Measures.”

Conference Call Information

athenahealth will conduct a conference call today, May 6, 2008, at 4:30 p.m. Eastern Time to discuss its financial results, quarterly highlights and management’s outlook for future financial and operational performance. To participate in athenahealth’s live conference call and webcast, dial 877-856-1955 or 719-325-4753 (international), and use confirmation code: 1991134. A live webcast and replay will also be available shortly after the call is completed on the Company’s investor web site: http://investors.athenahealth.com/events.cfm. A replay of the conference call will be available by calling 888-203-1112 or 719-457-0820 (international), pass code 1991134.

Source: ATHENAHEALTH