The plan, revealed on the sidelines of the Bali climate change conference, aims to preserve up to 1 million hectares (nearly 2.5 million acres) of forest on the Indonesian half of Borneo island.
As many as 50,000 orangutans have been lost over the past 35 years due to shrinking habitat, and "if this continues, these majestic creatures will likely face extinction by 2050," Indonesian President Susilo Bambang Yudhoyono said.
"To save orangutans, we must save the forests," he said.
Two thirds of Borneo's 30 million hectares (74 million acres) of primary forest have already been destroyed and environmental groups say the remainder is disappearing at a rate of 300 football fields per hour.
The Nature Conservancy, a coalition of non-governmental groups, pledged US$1 million (EUR680,000) to the program, which "could lead to 9,800 orangutans being saved," said Erik Meijaard, a senior ecologist for the coalition.
As of January 2004, about 6,650 Sumatran orangutans and 55,000 Borneo orangutans remained in the wild, while rapid deforestation has directly and indirectly led to around 3,000 orangutan deaths every year since 1970, the organization said.