The Yasuni National Park was established in 1979 and subsequently expanded in 1990 and 1992 and is Ecuador's largest mainland park encompassing 962,000 hectares. Located in the Napo province and only 190 miles from Quito, the park is south of Rio Napo and includes most of the watersheds of Rios Yasuni and Nashino, and large parts of Rio Tiputini. Because of the importance of the park's incredible biodiversity, UNESCO has declared Yasuni an international biosphere reserve.

Little scientific research has been done in the park to date making it one of the most important areas for recent conservation efforts by organizations such as Conservation International and the Nature Conservancy, Natural Resources Defense Council. Many of the Park's flora has not yet been recorded and in some areas it is believed that there is more than 200 species of trees per hectare. There are many types of vegetation, e.g., riparian, flooded forest or varzea, as well as firm ground forest, where relevant plant species vary over the hills and plateaus: balsa, crecopia, morete, palms, chonta palm, pambil, ficus, silkcotton, capirona, peanut trees, cinnamon, dragon's blood, jacaranda and many legumes.

In terms of fauna the park has: piranhas, catfish and many ornamental varieties; reptiles, anacondas, boa constrictors, crocodiles, turtles and several amphibians, invertebrates and insects. Birds: king buzzards, harpies, giant tinamou, falcons, fishing eagles, royal herons, macaws and parrots. Mammals: dolphins, manatees, tapirs, boars monkeys and giant armadillos. Within the park area live several Indian groups like the Quichuas del Napo and the Huaoranis. The Huaorani Indian tribe lives in the Tiputini, Yasuni, Cononaco and Nashino river basins, as well as on lagoon shores and navigable streams.

In 1991, despite Yasuni's protected status, the Ecuadorian government gave the US-based oil company Conoco the right to begin oil exploitation. Conoco was replaced by Maxus Oil Consortium, a subsidiary of Du Pont. Areas within the reserve have been degraded as a result of oil drilling and both local and national conservation organizations are working to protect this world treasure.