Traumatic brain injury (TBI) is a common cause of acquired disability during childhood. While much is now known about outcome following TBI in the school-aged population, recovery in infants and young children is less well documented. The aim of this study was to examine neurobehavioural function following TBI during early childhood, to plot recovery over the 30 months post-injury and to identify predictors of outcome. The study compared three groups of children, sustaining injuries of different severity (mild = 14, moderate = 46, severe = 24), aged 2.0-6.11 years at injury, with a healthy control group (n = 33). The groups were similar with respect to pre-injury adaptive and behavioural function, psychosocial characteristics, age and gender. Using a prospective, longitudinal design, intellectual, language and memory functions were investigated acutely post-injury and again at 12 and 30 months post-injury. Results suggested a strong association between injury severity across all neurobehavioural domains. Further, 30 month outcome was predicted by multiple factors including injury severity, socio-economic status, pre-injury adaptive abilities and age, with pre-injury child behaviour and specific lesion characteristics playing surprisingly little role. In conclusion, children with more severe injuries, lower pre-injury adaptive abilities and lower socio-economic status are at greatest risk of long-term neurobehavioural impairment, even several years post-injury.