NEW YORK, (AFP) - Mr Bill Gates, one of the world's richest men and highest profile aid donors, says he does not care if he is forgotten after his death - as long as polio and other major diseases have been eradicated.

"I don't need to be remembered at all," the co-founder of Microsoft, 57, told AFP in New York.

Mr Gates has a fortune estimated by Forbes at US$61 billion (S$75 billion), second only to Mexican telecoms tycoon Carlos Slim, and the satisfaction of knowing that Microsoft products are at the heart of computers in every corner of the world.

But he says that since quitting the running of Microsoft and focusing on his Bill and Melinda Gates Foundation, it is the world's poorest that have his attention.

"None of the people who are at risk of polio know anything about me, nor should they. They are dealing with day to day life and the fact that their child might get crippled," Mr Gates said in an interview at a posh Manhattan hotel.

Already the foundation has paid out US$25 billion to projects fighting disease and extreme poverty. There's currently about US$36 billion left in the pot - and it's all going to go.

"My wife and I have decided that our foundation will spend all its money within 20 years of when neither of us are around, so we're not trying to create some perpetual thing," Mr Gates said.

Target number one is polio, which has now been eradicated in India. Mr Gates says a worldwide end to the crippling childhood disease is feasible, with only Afghanistan, Nigeria and Pakistan the trouble spots.

"Within my lifetime, polio's not the only disease we should be able to eradicate. Even malaria - although that's more like a several decades effort - should be within reach," he said.

Mr Gates said that traditional government aid packages from rich countries to poor countries have been inefficient, or worse. "A lot of that was about buying friendship and almost shouldn't be labelled aid," he said, referring to the Cold War era, when Western and Soviet programs fought for influence in Africa and elsewhere.

The way forward, Mr Gates said, is to take a page from the corporate playbook and tie aid to specific goals, with close monitoring of progress.

"Business is always focused on measurements and if they get it wrong, they don't get capital and in extreme cases the company goes out of business," he said.

"Government and philanthropy don't naturally do the same thing," he said.