Neurocytomas gained importance since 1995, which is reflected by the increasing number of reports on this entity. This study was performed to determine the best available treatment for typical and atypical neurocytomas (MIB-1 labeling index >3%, atypical histology) in various age groups ( <or=18 years, >18 years). The data of all neurocytoma patients reported since 1982, when this entity were reviewed for age, gender, extent of resection, MIB-1 labeling index, histology, radiotherapy, and outcome of therapy. Patients were treated with complete resection alone (CTR), CTR plus radiotherapy (CTR + RT), incomplete resection alone (ITR), or ITR plus radiotherapy (ITR + RT). If the reported data were incomplete, the authors were contacted for additional data. Follow up had to be at least 12 months. Data were complete in 438 patients (73 children, 365 adults). Three hundred and fifty-one patients had typical, 87 atypical lesions. Typical lesions were associated with better local control and survival than atypical lesions (P < 0.001). CTR was superior to ITR (P < 0.001). After CTR, outcome was not significantly improved by RT. After ITR, RT improved survival in typical lesions (P = 0.03) and atypical lesions (P = 0.05), not in children (P = 0.16). Local control was improved in all groups (P < 0.001, children P = 0.01). Doses >54 Gy appeared beneficial after ITR of atypical lesions. In children, <or=50 Gy and >50 Gy were comparable.CTR does not require post-operative RT. Following ITR, RT improves outcome. Of 50-54 Gy appear sufficient for typical lesions, 50 Gy for children. Atypical lesions require 56-60 Gy.