The majority of persons exposed to a disaster do well and have only mild, transitory symptoms. However, some individuals develop psychiatric illness postdisaster. Such illnesses include those that are secondary to physical injury and sickenss as well as specific trauma-related psychiatric disorders such as acute stress disorder. The extent of the psychiatric morbidity and mortality that develops in individuals in the community depends on the type of disaster, the degree of injury sustained, the amount of life threat, and the duration of community disruption. In this paper we examine the posttraumatic responses of direct concern to psychiatrists working in a community exposed to a disaster. We review the epidemiology of posttraumatic responses, the interface of psychiatry and traumatic stress, the psychiatric disorders associated with trauma, and psychiatric consultation to the disaster community. Overall, psychiatric intervention after a disaster is based on the principles of preventive medicine and includes community consultation and outreach programs with the goals of identifying high-risk groups, promoting community recovery, and minimizing social disruption.