The benefits and risks of any particular GM crop depend on the interactions of its ecological functions and natural history with the agroecosystem and ecosystems within which it is embedded. These evolutionary and ecological factors must be considered when assessing GM crops. We argue that the assessment of GM crops should be broadened to include alternative agricultural practices, ecosystem management, and agricultural policy. Such an assessment would be facilitated by a clearer understanding of the indirect costs of agriculture and the ecological services that support it. The benefits of GM crops should be compared to those of other means of agricultural intensification such as organic farming, integrated pest management, and agricultural policy reform. A gradual and cautious approach to the use of GM crops that relies on a truly comprehensive risk assessment could allow people to reap substantial benefits from GM crops while mitigating their serious risks. Copyright © 2000 by The Resilience Alliance.