Two patients aged 6 and 5 years old with Mutism after posterior fossa surgery are presented. One of them has vermian medulobastoma and the other one has vermian asteroeytoma.

Postoperative, both of them were mute without distorbance of consciousness, language comprehension, or lower motor cranial nerve function. The disorder lasted 1 month in one case and about 3 month in the other one. Speech was regained after a period  of dysarthria, but both of them gradually became fluent. The mechanism of cerebellar Mutism is briefly discussed.