Morbidity and mortality associated with all-terrain vehicular accidents is climbing at a steady rate. These accidents frequently result in multiorgan system trauma. A retrospective study of all victims involved in three-wheel motor vehicle accidents admitted to the UCSD Trauma Unit between July 1980 and July 1985 is presented. Injury severity was assessed using the Abbreviated Injury Scale (AIS) and the Injury Severity Score (ISS). The average patient age was 23.3 years with 30% under 16 years of age. There was a male to female ratio of 14:1. The average hospital stay was 12.4 days. Six percent died as a result of their injuries. Injuries to the head and neck were sustained by 83.3% of patients, facial injuries by 46.6%, injuries to the chest by 13.3%, and injuries to the pelvis and abdomen by 13.3%. Thirty percent suffered injuries to the extremities and over 50% had abrasions, contusions, and/or lacerations. Physicians, the public, and state and federal agencies are urged to promote safer use of these recreational vehicles.