In collaboration with outside experts, the WHO Collaborating Centre for Neurotrauma at the Karolinska Institute, Stockholm, Sweden, has assembled a task force to undertake a best-evidence synthesis of the literature on mild traumatic brain injury. The task force has addressed the epidemiology, diagnosis, prognosis, treatment and economic costs of mild traumatic brain injury in order to make recommendations to reduce the medical as well as the social consequences of mild traumatic brain injury.