Objective: To examine the contributions of injury severity,physical and cognit ive disability, child and family function to outcome 30 months after traumatic b rain injury (TBI) in children. Design: A prospective, longitudinal, between grou p design, comparing function before and after injury across three levels of inju ry severity. Subjects: One hundred and fifty children, 3.0-12.11 years old, adm itted to hospital with a diagnosis of TBI. The sample was divided according to i njury severity: mild (n = 42), moderate (n = 70), severe (n = 38).Children with a history of neurological, developmental, and psychiatric disorders were exclude d from participation. Main outcome measures: Post injury physical function, cogn itive ability (incorporating intellect, memory, and attention), behavioural and family functioning, and level of family burden.Results: A dose-response relatio n was identified for injury severity and physical and cognitive outcome, with si gnificant recovery documented from acute to six months after TBI. Behavioural fu nctioning was not related to injury severity, and where problems were identified , little recovery was noted over time. Family functioning remained unchanged fro m preinjury to post injury assessments. The level of family burden was high at b oth six and 30 months after injury, and was predicted by injury severity, functi onal impairment, and post injury child behavioural disturbance. Conclusions: The se results suggest ongoing problems for the child and significant family burden 30 months after TBI. The nature and severity of the physical and cognitive probl ems are closely related to injury severity,with child and family function predic ted by psychosocial and premorbid factors. Objective: To examine the contributions of injury severity, physical and cognit ive disability, child and family function to outcome 30 months after traumatic b rain injury (TBI) in children. Design: A prospective, longitudinal, between grou p design, comparing function before and after injury across three levels of inju ry severity. Subjects: One hundred and fifty children, 3.0-12.11 years old, adm itted to hospital with a diagnosis of TBI. The sample was divided according to i njury severity: mild (n = 42 ), moderate (n = 70), severe (n = 38) .Children with a history of neurological, developmental, and psychiatric disorders were excluded d from participation. Main outcome measures: Post injury physical function, cognitization ability (incorporating intellect, memory, and attention), behavioral and family functioning, and level of family burden. Results: A dose-response relatio n was identified for injury severity and physical and cognitive outcome, with si gnificant recovery documented from acute to six months after TBI. Behavioural fu nctioning was not related to injury severity, and where problems were identified, little recovery was noted over time. Family health remains unchanged fro m preinjury to post injury assessments. The level of family burden was high at b oth six and 30 months after injury, and was predicted by injury severity, functi onal impairment, and post injury child behavioral disturbance. Conclusions: The se results suggest suggest problems for the child and significant family burden 30 months after TBI. The nature and severity of the physical and cognitive probl ems are closely related to injury severity, with child and family function predictive ted by psychosocial and premorbid factors.