In 1963, Suzuki ectc described in multiple progressive intracranial arterial occlusion and named“Moya Moya”disease. Many cases of Moya Moya disease had been reported and discussed by some Japanese Authors and they asserted that Moya Moya disease is characterized by the intracranial congenial of developmental anomaly apparently confined to Japanese. But more recently, this disease have been reported by some non-Japanese Authors, in the United Sates, Europe and Korea. We have experienced 6 cases of cerebrovascular Moya Moya disease from August 1976 to March 1979. We were proved by carotid and vertebral angiogram and clinical assessment. The results are as follows; 1. Age distribution was ranged from 7 to 41. Age under 20 were 4 cases and 4 cases were male and 2 females. 2. There were no contributory factors to cerebrovascular Moya Moya diseases with regard to familial back ground. 3. Clinical manifestations were mainly headache, vomiting, convulsion, hemiparesis and visual dis urbance. 4. Angiographic findings reveal occlusion or stenosis of internal carotid artery at the supraclinoid portion in all cases except for one (petrosal region) and also abnormal fine vascular network, poor or non-visualization of Anterior and Middle Cerebral Artery but relatively normal opacification of posterior cerebral artery. 5. Among these 6 cases, there was no evidence of subarachnoid hemorrhage or aneurysm on cerebral angiography.