Using data from the Trauma Audit Research Network, we investigated the costs of acute care in patients > or = 18 years of age hospitalised for traumatic brain injury between January 2000 and December 2005 in England and Wales. Traumatic brain injury patients were defined and stratified using the Abbreviated Injury Scale. A total of 6484 traumatic brain injury patients were identified; 22.3% had an Abbreviated Injury Scale score of three, 38.0% of four and 39.7% of five. Median age (IQR) was 42 years (28-59) and 76.7% were men. Primary cause of injury was motor vehicle collisions (42.4%) followed by falls (38.0%). In total 23.7% of the patients died before discharge. Hospitalisation costs averaged 15,462 pounds sterling (SD 16,844 pounds sterling). Costs varied significantly by age, Glasgow Coma Score, Injury Severity Score, coexisting injuries of the thorax, spine and lower limb, hospital mortality, availability of neurosurgical services, and specialty of attendants seen in the Accident and Emergency department.