Research has begun to identify early markers that predict survival after traumatic brain injury. In this study, trauma and biochemical indicators of severity were used to predict quality of life in 61 adults with traumatic brain injury and no damage to other organ systems. Severity markers available within 24 hours of injury were predictive of later psychosocial, behavioural and social role functioning. Multiple regression analyses demonstrated that the Glasgow Coma Scale, plasma glucose levels, leukocyte cell count and serum potassium concentration accounted for 12% to 66% of variance in certain measures of later quality of life. The importance of health-care resource allocation and psychosocial and behavioural intervention to the outcome after moderate traumatic brain injury is discussed.