Sport-related head injuries are a common clinical problem. Most head injuries in young athletes are mild traumatic brain injuries or concussions. The highest number of sport-related concussions has been reported in American football. In addition to the well described physical and psychosocial growth, there is ongoing neurocognitive development of the brain during childhood and through adolescence. This developmental process has direct implications in the assessment and management of head injuries in young athletes. Research on the management and long-term outcome following brain injuries in young athletes is limited. Traditionally, the assessment of concussion has been based on clinical history and physical and neurological examination. Increasingly, neuropsychological testing, especially computerised testing, is providing objective measures for the initial assessment and follow-up of young athletes following brain injuries. Numerous guidelines have been published for grading and return to play criteria following concussion; however, none of these have been prospectively validated by research and none are specifically applicable to children and adolescents.