One hundred and one consecutive patients with hypertensive cerebellar hemorrhage were analyzed to determine the criteria for surgery. New criteria based on the patient's Glasgow Coma Scale score at admission and the maximum diameter of the hematoma, as disclosed by computed tomography, are proposed from a retrospective analysis of 52 earlier cases. The criteria are as follows: 1) patients with Glasgow Coma Scale scores of 14 or 15 and with a hematoma of less than 40 mm in maximum diameter are treated conservatively; 2) for the patients with Glasgow Coma Scale scores of 13 or less at admission or with a hematoma measuring 40 mm or more, hematoma evacuation with decompressive suboccipital craniectomy should be a treatment of choice; and 3) for the patient whose brain stem reflexes are entirely lost with flaccid tetraplegia or whose general condition is poor, intensive therapy is not indicated. The validity of these criteria was tested and confirmed in 49 recent cases.