CT findings in eight cerebrovascular moyamoya disease were compared with carotid angiographic findings and theresults were as follows; 1. The patient's age was ranged from 2 to 49 years. Of eight patients, five were lessthan 17 years old and the rests were two 23 years and one 49 years of age. 2. Except one 6 years ol boy, all ofthem were female patients. 3. In precontrast CT scan of 8 cases, 6 cases of cortical atrophy, 6 cases ofventricular dilatation and 5 cases of low density area were observed. In postcontrast study the children groupshows abnormal contrast enhancement in 3 out of 5 patients but all adult reveal no contrast enhancement. 4. Theisodense area in CT were thought to represent good collateral manifested by angiographic moyamoya vascular networkand leptomenigeal anastomosis while the low density area in CT appears to poor colleaterals manifested bytransdural anastomosis. 5. To evaluate the possiblity of this disease, carotid angiography should be performed tothe hemiplgic child who shows multiple low density area and abnormal enhancement in CT scan. 6. CT is not onlyreliable for evaluation of ventricular hemorrhage but also brain damage in patients with moyamoya disease.