Purpose/Objective(s): To characterize patterns of failure and clinical-and treatment-related predictors of survival in adult medulloblastoma. Materials/Methods: The clinical records of 57 adult patients (age 18 years) with histologically proven medulloblastoma treated at our institutions between 1986 and 2015 were retrospectively analyzed. All patients had disease confined to the craniospinal axis at presentation, and 7 patients had M+ Chang stage. Lesions were midline in 23 cases and lateral in 34. Histological subtypes were as follows: 31 classic, 20 desmoplastic and 6 anaplastic. Gross total resection was achieved in 37 patients, and the remaining 20 patients underwent subtotal resection. All patients received post-operative radiotherapy, with median craniospinal dose of 36 Gy and posterior fossa dose of 54 Gy. Thirty-eight patients received chemotherapy (14 pre-radiation, 24 post-radiation). Results: With a median follow-up period of 5.2 years, 18 patients experienced recurrences. At 5 years, overall survival rate was 87%, and eventfree survival rate was 70%. The 5-year posterior fossa control rate was 81%. Twenty-two percent of all relapses occurred more than 5 years postradiotherapy. The posterior fossa was the most common site of relapse. In univariate analysis, radiotherapy duration of 7 weeks or less was associated with improved overall survival (PZ0.02). Extent of resection (PZ0.001), standard-risk grouping (PZ0.006) and radiotherapy duration of 7 weeks or less (PZ0.007) were statistically significant predictors of improved posterior fossa control. In multivariate analysis, completion of radiotherapy in 7 weeks or less was predictive of improved posterior fossa control (PZ 0.04) and overall survival (PZ 0.05). Conclusion: Patients with adult medulloblastoma have survival rates similar to their pediatric counterparts, but late and distant relapses are common. The delivery of radiation therapy over a shorter interval is associated with improved local control and survival.