WASHINGTON — The billionaire co-founder of Microsoft is touting what he sees as an investment with enormous returns - the money spent to improve health care in poor countries and the millions of lives saved because of it.

"Global health money improves lives more effectively than any other spending," Bill Gates told a roundtable discussion Tuesday on a new initiative called The Living Proof Project that is being launched by Gates and his wife, Melinda.

The two were in Washington to urge policymakers and others to continue or even increase federal dollars spent on programs to fight AIDS, malaria and other diseases in underdeveloped nations.

"We're seeing a lot of hope on the ground," said Melinda Gates. But "you're not hearing about the positive changes that are happening because of these American investments."

The success stories they highlighted:

• An AIDS relief program called PEPFAR, created in 2003 under former President George W. Bush. PEPFAR, the President's Emergency Plan For AIDS Relief, has helped save an estimated 1.2 million lives by expanding access to HIV prevention and treatment.
• A global initiative known as the GAVI Alliance that has helped immunize children in poor countries, preventing an estimated 3.4 million deaths in less than a decade.

The Bill&Melinda Gates Foundation, based in Seattle, spent about $1.8 billion last year on global health issues. The United States spent about $8 billion on global health in the last year.

Bill and Melinda Gates both said foreign aid from the United States is crucial to cut deaths worldwide, especially among children. The two planned to ask lawmakers, administration officials and others at a presentation Tuesday night to pledge to cut child deaths by nearly 50 per cent - from about nine million preventable deaths a year now, to five million by 2025.

The Gates' Living Proof Project will share personal stories from people who have benefited from U.S. spending on global health.