A 70-year-old woman was admitted with a diagnosis of subarachnoid hemorrhage. She had complaints of sudden severe occipital headache and vomiting. Examination showed right blepharoptosis, mild right mydriasis, depression of the right corneal reflex, dysphagia, and left sensory disturbance. Computerized tomography revealed a high density area in the fourth and third ventricles. External ventricular drainage was performed, but the patient took a downhill course and died 6 months later. Necropsy revealed tumor tissue arising from the posterior aspect of the pontomedullary junction growing exclusively in the fourth ventricle. Histological examination showed a hemangioblastoma with endothelial proliferation, foam cells, swollen and lipid-filled endothelial cells, and varying sizes of dilated veins. It seems quite reasonable to assume that the hemorrhage in this case was due to rupture of the abnormally dilated veins around the tumor.