Primitive neuroectodermal tumors (PNETs) are tumors which primarily consist of undifferentiated round neuroepithelial cells. Central nervous system PNETs can be divided into two genetically distinct groups: infratentorial PNET (iPNET)/medulloblastoma and supratentorial PNET (sPNET). Currently, the comparative outcome of adult patients with sPNETs and iPNETs is unknown. In this study we have utilized the Surveillance, Epidemiology, and End Results database to perform a comparative analysis of 103 cases of adult sPNET and 669 adult medulloblastoma cases. Additionally we have analyzed various factors to identify their prognostic significance and characterize the optimal treatment for these tumors. Patients with sPNETs were seen to have a significantly worse survival than those diagnosed with medulloblastomas (16 vs. 155 months, p < 0.0001). Elderly patients (15 vs. 114 months, p < 0.0001) and those over the age of 40 (68 vs. 147 months, p < 0.0001) experienced significantly worse survival than younger patients. In contrast, radiotherapy (143 vs. 26 months, p < 0.0001), surgical resection (116 vs. 22 months, p = 0.0010) and the extent of resection (EOR) (173 vs. 81 months, p = 0.0005) resulted in significantly improved patient survival. Multivariate analysis revealed age greater than 40 years (HR: 1.57; 95 % CI: 1.17-2.11; p = 0.0028) and sPNET pathology (HR: 3.41; 95 % CI: 2.47-4.72; p < 0.0001) to be poor prognostic factors for survival while radiotherapy (HR: 0.52; 95 % CI: 0.38-0.71; p < 0.0001) and the EOR (HR: 0.73; 95 % CI: 0.55-0.96; p = 0.023) were associated with significantly improved survival. The treatment of sPNETs should therefore include maximal surgical resection when feasible followed by radiotherapy as these treatments have been demonstrated to confer a survival benefit. Additional studies are needed to identify effective chemotherapeutics and specific treatment regimens for adults with sPNETs.