Kerry N. Weems, a longtime federal health official, is President Bush's choice to oversee the Medicare and Medicaid programs.

If confirmed by the Senate, Weems would succeed Mark McClellan. The White House planned to announce the nomination later Thursday, an administration official said.

Weems is deputy chief of staff to Health and Human Services Secretary Mike Leavitt. He also has served as an acting assistant secretary overseeing budget and technology issues.

The Centers for Medicare and Medicaid Services is the agency that oversees federal health programs for the elderly, disabled and the poor.

The president will also nominate Tevi David Troy to be deputy secretary at HHS. Troy is the deputy assistant to the president for domestic policy.

"Both bring a broad array of knowledge, management experience and expertise that will enhance our ability to advance effective policies to improve Americans' health," Leavitt said.