Based on the 242 consecutive surviving head injury cases and 132 general trauma cases, this study examined the contribution of brain and non-brain injuries to cognitive and psychosocial outcome 1 month postinjury. The study also examined the relationships among various head injury severity indices. The head injury severity indices were all correlated but patients with Glasgow Coma Scale scores in the mild range had broadly ranging scores on the other head injury severity indices (Abbreviated Injury Scale and time to follow commands). Neuropsychological outcome was related to brain injury severity, but was not independently influenced by severity of other systems injuries. Psychosocial outcome related to both brain and non-brain injuries independently. When evaluating trauma outcome, it is important to consider the contributions of both brain and other system injuries.