Medullomyoblastoma is a rare histologic variant of medulloblastoma. We report a case of medullomyoblastoma occurring in the cerebellar vermis. A 12-year-old girl presented with a 3-month history of headache, nausea, vomiting and unsteadiness of gait. Magnetic resonance imaging (MRI) revealed a mass lesion in the cerebellar vermis. A suboccipital craniectomy was perfomed to remove a tumor. Immunohistochemical studies confirmed the presence of both a primitive neuroectodermal component and rhabdomyoblastic differentiation, consistent with the diagnosis of medullomyoblastoma.