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 than any other spending,' Bill Gates told a roundtable discussion on 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 programme 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.

The Bill & Melinda Gates Foundation, based in Seattle, spent about US$1.8 billion (S$2.5 million) last year on global health issues. The United States spent about US$8 billion on global health in the last year.