Substance use is significantly associated with physical injury, yet relatively little is known about the prevalence of specific substance use disorders among trauma patients, or their associated sociodemographic characteristics. We evaluated these issues in an unselected sample of 1,118 adult inpatients at the University of Maryland Shock Trauma Center, Baltimore, MD, who were interviewed with the psychoactive substance use disorder section of the Structured Clinical Interview for DSM-III-R. Among trauma inpatients, lifetime alcohol users (71.8% of subjects) were more likely male; users of illegal drugs (45.3%) were also more likely to be younger, unmarried, and poor. Patients with current drug abuse/dependence (18.8%) were more likely to be non-white, less educated, and poor; those with current alcohol abuse/dependence (32.1%) were also more likely male, unmarried, and older. These findings highlight the need for screening for substance use disorders in trauma settings and referral of patients to substance abuse treatment programs.