The effects of seat belts and the use of alcohol and drugs have been studied as etiological factors in facial trauma to occupants of motor vehicle accidents (MVAs). During a 15-month period, 461 patients were admitted to a regional trauma center as a result of injuries sustained in MVAs. Two hundred thirty-seven (51%) of these patients had facial trauma. Facial trauma was the single most common injury in these patients. One hundred eighty-five patients (78%) had major soft tissue injury, and 52 patients (22%) had facial bone fractures. Forty-two of 237 patients (18%) with facial trauma were wearing seat belts compared with 74 of 224 patients (33%) without facial trauma who were wearing seat belts at the time of the accident. Large numbers of patients who were wearing seat belts at the time of the accident had minor injuries and were never admitted to the hospital. Sixty-five of 224 patients (24%) without facial trauma and 121 of 237 patients (51%) with facial trauma tested positive for alcohol or drugs. The majority of the patients who tested positive for alcohol had blood alcohol levels of more than 100 mg/dL. Head injuries and blunt chest trauma were most commonly associated injuries in these patients. This study suggests that use of alcohol and drugs in occupants of the motor vehicle had a major effect on the etiology of facial trauma. Also it supports the data that suggests that the use of seat belts prevents a wide range of injuries including facial trauma in MVAs.