Microsoft Chairman Bill Gates announced today he will be leaving his daily role at the company he founded to focus on global health and education at the Bill & Melinda Gates Foundation. But he's not rushing out — the transition process will take two years, Microsoft said.

Gates will continue to serve as Microsoft's chairman and adviser on key development projects even after the transition is complete in July 2008, the company said. The two-year time frame is designed to work toward a smooth transfer of strategy and knowledge.

Gates has played a direct role in guiding the company since its inception in 1975, but more recently has said he intended to spend time with his foundation in the future. "This was a hard decision for me," Gates said in a statement. "I'm very lucky to have two passions that I feel are so important and so challenging. As I prepare for this change, I firmly believe the road ahead for Microsoft is as bright as ever."

Steve Ballmer, who took over as the company's chief executive from Gates in 2000, said Gates' impact on the company won't diminish. "We will contrinue his tradition of thinking big, executing bigger," he said.

In the meantime, Microsoft Chief Technical Officer Ray Ozzie will immediately take over Gates' title as chief software architect and "begin working side by side with Gates on all technical architecture and product oversight responsibilities, to ensure a smooth transition," the company said in a statement.

Chief Technical Officer Craig Mundie will assume the new title as chief research and strategy officer and work closely with Gates to take over responsibility for the company's research and incubation efforts, while also working with General Counsel Brad Smith on intellectual property and technology policy , the company said.

"Bill and I are confident we've got a great team that can step up to fill his shoes and drive Microsoft innovation forward without missing a beat," Ballmer said.

Gates said, "I've had a chance at great wealth, and with great wealth comes great responsibilty. It is time to give back to society those resources in the best possible way to help those in need."

Ozzie, who founded Groove Networks in 1997, was named chief technical officer at Microsoft when the company acquired Groove Networks in April 2005.

"Our business and technical leadership has never been stronger, and Microsoft is well-positioned for success in the years ahead," Gates said. "I feel very fortunate to have such great technical leaders like Ray and Craig at the company."

Gates added: "I remain fully committed and full time at Microsoft through June 2008 and will be working side by side with Ray and Craig to ensure that a smooth transition occurs."

He also said, I don't see a time in the future where I won't be chairman of the company. "I want to have that asosciation my entire life and I'm commited to do that."

Seattle Times technology reporters Kim Peterson and Tricia Duryee contributed to this report.