Increasing scarcity of natural resources is currently of serious concern for many people in the community of Sarayaku. In this thesis, a combination of participatory research, ecological modelling, GIS, and economic experiments was used to identify and examine problems regarding natural resource use in the community. The study showed that the interactions between humans and nature in the area have undergone significant changes during the last four or five centuries, related to changes in population density, settlement pattern, and technology. The community is only partly integrated in the cash economy, and most food is locally produced. Wild game and fish are important sources of dietary protein and fat. Fields and fallows make up about 4% of the area, whereas the rest is dominated by old-growth forest. Near the village fallows dominate the landscape, and the distance from settlements to old-growth forest has increased. Several major game species are severely depleted, particularly in the vicinity of the village. The problem of game depletion can partly be explained as a “tragedy of the commons”, i.e. the result of uncoordinated resource withdrawal by a large number of appropriators, in which each one behaves in a self-interested manner. However, unawareness of the impact of hunting on game populations has also been a contributing cause. The community has long had some capacity for managing resources in a coordinated way, as shown by the existence of rules for how to harvest palm leaves for thatch. During recent decades, the community has created a democratic consensus-based community organization that has developed into a local government. Increasingly, this organization is dealing with regulating natural resource use, in order to solve conflicts and improve sustainability of resource use. Oil development threatens to damage the environment and undermine the local democracy. If this can be avoided, however, improving the sustainability of resource use is an achievable goal.