The role of ecological research in supporting development of one aspect of sustainable use, sustainable agriculture, was evaluated at a conference organized by the U.S. Environmental Protection Agency (EPA) in Arlington, Virginia, July 22-23, 1991. Agriculture contributes to many of the environmental problems for which EPA is seeking solutions; for example, nonpoint source pollution, contamination of groundwater, air toxics, and loss of biodiversity. EPA's new emphasis on prevention rather than mitigation of environmental problems makes the potential environmental benefits of sustainable agriculture attractive to the Agency. EPA's growing expertise in ecology, combined with a recognition of the importance of ecological knowledge as a foundation for sustainable agriculture, led to the conference theme. The objectives of the conference included examining the socioeconomic and political context within which sustainable agriculture must develop, discussing the application of ecological knowledge to developing a sustainable agriculture within this context, and identifying research priorities. These issues were addressed by a series of papers that were presented at the conference and are printed in this volume.