Two cases of glioblastoma multiforme of the cerebellum are reported. Case 1, a 55-year-old male, was admitted in 1981 with a 3-week history of intermittent headache, vomiting, and gait instability. Case 2, a 27-year-old female suffering from von Recklinghausen's disease, was admitted in 1973 with a 6-week history of headache, vomiting, and blurred vision. On admission, cerebellar symptoms and bilateral papilledema were observed in both patients. Neuroradiological studies, including computed tomography scan and angiography, were of little help in predicting the exact nature of these tumors before surgery. At the operation, a tumor growing mainly in the right cerebellar hemisphere was found in each patient. On histological examination, hypercellularity with pleomorphism, small patches of necrosis, and vascular endothelial proliferation were noted, which appeared to be indistinguishable from those of cerebral glioblastoma. In spite of repeated operations followed by chemoradiotherapy, both patients died of tumor recurrence, 38 months and 25 months after the onset of the symptoms, respectively. Glioblastoma multiforme of the cerebellum is very rare and accounts for approximately 0.6% of all glioblastomas reported in the recent literature. Only 82 cases of the cerebellar glioblastoma have so far been reported. The biological behavior of these tumors is in all respects identical to those of the cerebral counterparts.