The national disaster medical system is a new program established in 1981 to develop and implement a national policy to improve emergency preparedness for large-scale disasters. This article describes the background and purpose of this activity and delineates the elements of the system, which include a rapid medical response, patient evacuation, and definitive medical care. The program is designed to involve resources at the federal, state, and community levels. This article describes how local communities may participate in this initiative.