We compare existing nontimber forest product extraction systems in Petén, Guatemala, and West Kalimantan, Indonesia, to identify key ecological, socioeconomic, and political factors in the design and implementation of extractive reserves. Ecological parameters include the spatial and temporal availability of harvested products and the sustainability of harvesting practices from both a population and an ecosystem perspective. Socioeconomic and political factors include the presence or absence of well‐defined resource tenure rights, physical and social infrastructure, markets, and alternative land uses. We conclude that although extractive reserves can play a significant role in preserving tropical forests as a part of a broader land‐use spectrum, their effectiveness is highly dependent on prevailing local ecological, socioeconomic, and political conditions. Ultimately, extractive reserves should be regarded as one component of an overall approach to the problem of tropical deforestation. Copyright © 1993, Wiley Blackwell. All rights reserved