Microsoft Chairman Bill Gates has pledged $250 million toward the international effort to eradicate polio.
Gates announced his donation Wednesday night at a conference in San Diego for leaders of Rotary International. The group has been trying to match a $100 million donation from the Bill and Melinda Gates Foundation in 2007.
The Gates foundation has given $655 million to polio-eradication efforts since the late 1990s.
The 1.2 million-member Rotary International has raised more than $650 million since adopting the anti-polio cause in 1985 as its primary international mission.