McKelvey is being succeeded by William Pastore, a relative newcomer to the job board industry who joined the company as COO in October 2002. Pastore was promoted to president and COO in February.

In July, Monster disclosed that it might need to restate its 2005 financial results and results for and earlier years to account for stock option costs. In September, the company suspended its general counsel.

There has also been speculation about McKelvey's health. He was hospitalized in March with pneumonia.

"At this stage in my life, I simply can no longer dedicate the number of hours required by Monster's rapid global growth and the additional demands of time associated with the ongoing historical stock option grant review," McKelvey said in a statement announcing his resignation. "I believe that these managerial changes will assist the company in addressing the challenges that it faces today. Monster's continued growth and success have always been, and remain, my number one priority."

McKelvey is 71 and has been at the company for 39 years, according to Katherine Burns, global communications manager for Monster Worldwide in New York. He will remain on the company's board of directors, where he has been elected as chairman emeritus.

Pastore was en route to a satellite office in Maynard, Massachusetts, on Monday and could not be reached for comment. Prior to Monster, Pastore worked at Cigna Healthcare in various areas, including, operations, sales and marketing, technology and customer services. He also held several leadership posts at Citibank, where he worked for almost 25 years. For now, Pastore's COO position will not be filled.

The company tapped Pastore for the top job because of his ability to materialize strategic concepts, according to Burns. He was one of the driving forces behind several of Monster's recent key projects, including its international expansion into Mexico and its alliance with Philadelphia Media Holdings, which led to the launch of a co-branded job portal for the Philadelphia market.

"We want to grow globally but become local at the same time," Burns says.

Monster is already dabbling in some very interesting projects and will probably stay the course, according to Peter Weddle, CEO of Weddle's, a research and consulting practice based in Stamford, Connecticut.

Monster has 90 percent brand recognition, Burns says. In addition, the company has more than 61 million job seekers worldwide and a résumé database with approximately 52 million résumés. During the third quarter, Monster generated $206.8 million in revenue, up 31 percent from the same period a year earlier.

-Gina Ruiz