Medulloblastomas are embryonal tumors arising from the cerebellum and are the most common malignant brain tumors of childhood, with an incidence of 10-25% of primary CNS neoplasms. Medulloblastomas in adults are less common but they do occur. Like many tumors the exact cause is unknown but changes have been identified in genes and chromosomes that may play a role in the development of these tumors. Although the cause is unknown there are several studies that have ruled out many environmental factors. Medulloblastomas are diagnosed by clinical presentation as well as diagnostic tools. Patients with medulloblastoma present with a history of headaches, emesis, and lethargy which are commonly subtle and intermittent. Symptoms are most often related to hydrocephalus secondary to obstruction of the fourth ventricle. Diagnostic tools such as the CT and MRI play a significant role in helping to initially diagnose medulloblastoma as well as the workup following the treatment and or resection. Histologically medulloblastomas can be classified into 7 different types, which is important for further treatment. The definitive diagnosis of medulloblastoma is made on microscopic pathologic examination. Current treatment of medulloblastoma consists of surgically removing as much of the tumor as possible, followed by craniospinal radiation and or chemotherapy. Treatment plans are based on factors that indicate the risk of recurrence. How well a patient responds to treatment is affected in general by their age at the time of diagnosis, the size and extent of the tumor, the amount of mass that can be removed safely and the level of metastatic disease. It is now becoming clear that patients with certain subgroups of medulloblastomas have better long-term outcome in comparison to the others.