A case of mutism after removal of a vermian medulloblastoma from a 4-year-old girl is reported. Postoperatively, the patient was mute without disturbance of consciousness, language comprehension, or lower cranial nerve function. Computed tomography scans demonstrated no abnormal findings except for the surgical lesion in the posterior fossa. The mutism lasted for 78 days, followed by a period of dysarthria, but she gradually became fluent. The mechanism of "cerebellar mutism" is briefly discussed.