Patients who have severe trauma have been reported to have a substantially increased rate of seropositivity for human immunodeficiency virus when compared with the general population. We reviewed the records of 1226 consecutive Code-3 trauma patients who were treated at our institution in San Antonio, Texas, between 1987 and 1989. All of the patients had serum drawn to be tested for the human immunodeficiency virus. In contrast with previously published studies, only 0.8 per cent of these trauma patients were seropositive. There was no appreciable difference between the prevalence of seropositivity in patients who sustained blunt trauma and those who sustained penetrating trauma. Exposure to human immunodeficiency virus for medical personnel who care for trauma patients remains a concern, but the risk may be lower than previously reported.