The U.S. Air Force is entrusted with stewardship of a diversity of natural resources on installations throughout the United States. For many years these resources were managed with a commodities-based approach emphasizing multiple use, sustained yield, and the protection of single species regulated under the Endangered Species Act. Beginning in 1992, Air Force policymakers and field personnel recognized a need to adopt a new management policy. An ecosystem-based approach was adopted as a process for making, implementing, and evaluating decisions affecting the management of natural resources. This approach was implemented with a new policy directive, changes in funding priorities, and a new training course. We believe the ecosystem approach will better support the military mission and ensure the sustainability of natural resources on U.S. Air Force installations.