Fifty six patients with hypertensive cerebellar hemorrhage diagnosed by CT scan were hospitalized from November 1976 up to June 1984. The 35 male and 21 female patients ranged in age from 24 to 84 years, and 39 of them were operated on. The important factors related to prognosis of cerebellar hemorrhage were level of consciousness, size of hematoma on CT scan, and massive ventricular hemorrhage resulting in obstruction of the ventricular system. We classified the patient with cerebellar hemorrhage into 5 grades, according to the severity of these factors. Grade I indicates cerebellar signs without disturbance of consciousness and size of hematoma less than 25 mm measured by CT scan. Grade II indicates disturbance of consciousness (stupor), or progressive neurological deficits, and size of hematoma less than 50 mm without acute hydrocephalus. Grade III reveals disturbance of consciousness (stupor-semicoma), and size of hematoma less than 50 mm with acute hydrocephalus. Grade IV reveals severe disturbance of consciousness (semicoma), and size of hematoma less than 50 mm with massive ventricular hemorrhage. Grade V exhibits deep coma, and more than 50 mm diameter of hematoma. The prognosis of all of 9 patients in Grade I was good, Eleven out of 13 patients (85%) in Grade II and all of 9 patients in Grade III were alive. Fourteen out of 19 patients (74%) in Grade IV and all of 6 patients in Grade V expired in spite of operation. The patients of Grade I should be treated by conservative therapy. The patients of Grade II, Grade III, and Grade IV should be managed surgically. Surgical treatment for Grade V is not advisable.