SEATTLE, Washington - Bill Gates says he feels a responsibility to speak up for the world's poorest because they're likely to be hit hard as economic woes force governments to reduce contributions to foreign aid.

In his third annual letter, issued on Monday, the co-chairman of the world's largest charitable foundation expressed concern about budget cuts to the programs that transfer dollars from rich nations to poor ones, providing medical assistance, food aid, vaccines and other help.

The Microsoft co-founder and chairman says in the 24-page letter that not only is helping the poor with their medical needs and giving them the tools to be self-sufficient the right thing to do, it's also a good investment.

"Securing the conditions that will lead to a healthy, prosperous future for everyone is a goal I believe we all share," wrote the co-chair of the Seattle-based Bill & Melinda Gates Foundation.

In the letter, Gates outlines the ways helping people saves money over the long term: From cutting the cost to treat the sick by preventing their illnesses to increasing a child's earning potential and future contribution to society through education. He said British Prime Minister David Cameron gives him hope that not all countries have forgotten about the needs of the poor, noting that the United Kingdom has kept its promise to grow foreign aid spending despite the need to cut other programs.

"It is inspiring to see a leader stand up for what he believes is right, even when it isn't easy," Gates wrote.

Associated Press