The authors collected 53 consecutive cases of chronic subdural hematoma which were diagnosed by carotid angiography and brain scanning. There were 39 males and 14 females. The mean age was 45.6 years old. 80% of all cases had a history of head injury and one of the clinical manifestations of increased intracranial pressure as well as contralateral hemiparesis. The most common site of hematoma was fronto-parietal region. 42 cases were treated with simple drainage and 11 cases with membranectomy. Post-op. course was excellent in all cases of simple drainage, but in 2 cases of membranectomy, recollection of hematoma developed after surgery.