Prognostic factors for the outcome of patients with a chronic subdural haematoma were analysed in a consecutive study of 260 patients, regardless of the method of neurosurgical treatment. CT findings such as haematoma volume, midline shift and residual subdural collections had no influence on the outcome. The only statistically significant factor of importance for the outcome of patients with chronic subdural haematoma was the neurological condition at the time of treatment. Early diagnosis is therefore of major importance.