The aim of this study is to investigate predictive factors of post-traumatic syndrome in children with minor head injury. Prospective neurological, electroencephalographic and psychological investigations were performed in 98 children aged 3-13 years within 24 h after the trauma and 4-6 weeks later. Inclusion criteria for mild head injury were unconsciousness <10 min or none at all, lack of overt neurological symptoms and other complications requiring intensive care. Twenty-six of the children had been unconscious for a short period. Ten had suffered a skull fracture. Within the first 24 h, nearly all children reported acute symptoms of concussion and 64 of 98 showed abnormal EEG findings. After 4-6 weeks, 23 of 98 still exhibited post-traumatic complaints with headache, fatigue, sleep disturbances, anxiety and affect instability. Such post-traumatic symptoms did not correlate with somatic, neurological or electroencephalographic findings observed immediately after the injury or at the follow-up investigation. As opposed to the situation in more severe head trauma, post-traumatic syndrome after minor head injury in children is apparently not due to central nervous injury detectable by neurological examination or electroencephalography. Irrespective of the necessity of neuroradiological investigations and repeated EEGs in more severe and complicated head trauma, we discourage the routine EEG examination in very slight head injury and instead rather recommend parent and patient counselling.