Eighteen patients with poorly differentiated gliomas of the cerebellum were treated by the University of California San Francisco Neuro-Oncology Service between January 1977 and January 1987. Within this group pathologic diagnosis included five glioblastoma multiforme (28%), nine anaplastic astrocytomas (50%), and four mixed malignant gliomas (22%). The group included 13 male and five female patients with a median age at diagnosis of 23 years (range, 4-46 years). All patients underwent surgical resection, 16 of 18 received radiation therapy (12 limited-field irradiation and four whole-brain with or without a posterior fossa boost), and 16 of 18 received chemotherapy. Overall median survival was 31.5 months (range, 5-366 months). Ten patients (55%) died of recurrent disease with a median survival of 32 months (range, 5-128 months), two of whom manifested metastatic disease within the central nervous system (one parietal lobe and one cervical cord). Of the two extracerebellar metastatic recurrences, one patient failed at the junction of whole-brain irradiation and the cervical cord and one patient failed after inadequate posterior fossa irradiation. Eight patients (45%) are alive with a median follow-up of 27.5 months (range, 14-366 months). In this series recurrences of primary cerebellar anaplastic gliomas were locoregional failures. As a consequence, the authors suggest high-dose limited-field irradiation directed at the primary tumor as in their current strategy utilized for supratentorial gliomas.