Mass disasters (those that involve eight or more victims) can be either natural (most often floods or tornados) or man-made disasters, which include mass-transit accidents, fires, industrial accidents, terrorist attacks, and wars. Although the focus of this chapter is on responses to aircraft crashes, the authors advise that with little change, the response to an aircraft crash is appropriate for a wide variety of mass disasters. The medical examiner or coroner on an aircraft crash investigation team has the following major functions: identification of the victims; documentation of their injuries and disease processes and correlation of these findings with aircraft and crash-site evidence; communication with victims' families and the return of victims' property to them; and the release of information to the news media. These functions include autopsies and toxicological analyses of the flight crew, as well as examination of the aircraft. The role of disease and drug/alcohol intoxication in causing the crash must be addressed by the medical examiner. Victim identification involves fingerprinting, footprinting, and palmprinting of victims; and documentation of distinctive dental features, body measurements, radiological studies, and DNA identification procedures. Separate sections of the chapter discuss investigating teams, jurisdiction, counseling of friends and personnel to assist in dealing with posttraumatic stress, documentation, the search and recovery of victims, the collection and preservation of evidence, and bombs and explosion injuries. 2 tables, 17 photographic and graphic exhibits, and 25 references