Head injuries have been shown to account for between 4 and 22% of soccer injuries. Clinical and neuropsychological investigations of patients with minor head trauma have revealed organic brain damage. 69 active football (soccer) players and 37 former players of the Norwegian national team were included in a neurological and electroencephalographic (EEG) study to investigate the incidence of head injuries mainly caused by heading the ball. 3% of the active and 30% of the former players complained of permanent problems such as headache, dizziness, irritability, impaired memory and neck pain. 35% of the active and 32% of former players had from slightly abnormal to abnormal EEG compared with 13 and 11% of matched controls, respectively. There were fewer definitely abnormal EEG changes among typical 'headers' (10%) than among 'nonheaders' (27%). The former players were also subjected to cerebral computed tomography (CT), a neuropsychological examination and a radiological examination of the cervical spine. One-third of the players were found to have central cerebral atrophy and 81% to have from mild to severe (mostly mild to moderate) neuropsychological impairment. The radiological examination of the cervical spine revealed a significantly higher incidence and degree of degenerative changes than in a matched control group.