AbstractBackground: Post-operative cerebellar mutism is knowncomplication may occur following the excision of posteriorfossa tumors in paediatrics, specially seen with medulloblas-toma lesions. Post-operative Cerebellar Mutism (CM).Aim of Study: Post-operative cerebellar mutism is notuncommon after excision of posterior fossa tumors in pediat-rics. Evaluation of important risk factors e.g. type of tumor,size, site and infiltration of brainstem was studied in thiswork.Material and Methods: A series of 30 children withposterior fossa tumors were operated at Abo El-Reesh Hospital,Department of Neurosurgery in 2017. Their radiological dataand neurocognitive functions were investigated pre and post-operatively.Results: Cerebellar mutism developed in 9 children (30%) in the first few days post-operative, 7 males and 2 females. Age ranged from two years to twelve years. 7 cases were medulloblastoma and 2 cases were ependymom. There was infiltration of brainstem in most cases of cerebellar mutism. Mutism resolved in 8 cases.Conclusion: Cerebellar mutism could often occur follow-ing excision of posterior fossa tumors in pediatrics in firstdays following the surgery with favourable outcome. It mostlikely occurs following the resection of medulloblastomainfiltrating brainstem. The cerebellar ischemia and the cere-bellar edema may be possible causes for occurrence of cere-bellar mutism.