The authors present a case of cerebellar dermoid cyst, the only one found among the intracranial tumors operated at the Department of Neurology of the University of São Paulo Medicine School, between January 1945 and March 1963, thus confirming their rarity. A girl 4 years old presented intracranial hypertension plus cerebellar symptons which began two months before admission. The diagnois of meduloblastoma of the vermis based upon the clinical symptons and laboratory findings was made. In accordance to this diagnosis the lamina terminalis was opened and the patient was submitted to a series of cobalt irradiation therapy on the posterior fossa with slight improvement of the neurological picture. Osteomyelites of the bone flap developed with fever and convulsions; 8 days postoperatively the patient died. At necropsy dermoid cyst of right cerebellar hemisfere was found which at the histopathological examination showed tissues from the ectoderm and mesoderm.