This report examines the incidence of traumatic brain injury (TBI) in Australia in 1997-98, based on hospital separation data. It shows that TBI accounted for 7 per cent of all injury hospital separations. It also includes data on the age-standardised rate of TBI and the main causes of TBI among different age groups (the male rate was higher than the female rate in most age groups). Statistically significant state rate differences were recorded overall, but not among very severe cases. A recent decline in the rate of TBI was also noted but requires further assessment.