A summary of the presentation, diagnosis and therapy of head injury is given. The article is focussed on mild head injury, the most frequent type of head injury. The difference between concussion and contusion is explained. Symptoms and abnormalities found at neurological examination are discussed. The Glasgow Coma Scale is described as a tool to diagnose the severity of head injury. The value of additional radiological investigation is discussed. The therapy which depends on the severity of head injury and concomitant complications, is given. Information about eventual persisting complaints and deficits is important. After-care depends on the severity of the injury and the persistence of neurological signs and symptoms. Outcome measurement is done by the Glasgow Outcome Scale. It is emphasized that patients may exhibit persistent complaints although they return to work or school.