Abstract OBJECTIVE The standard treatment for intracranial germinoma has been radiotherapy covering the whole ventricle together with chemotherapy. Radiotherapy is important, but it is a cause of the late brain damages. Therefore, the recent clinical trials have been planned to evaluate the reduced radiation dose. The aim of this study was to evaluate the intracranial adverse events in the patients with intracranial germinomas treated in our hospital. PATIENTS AND METHODS 65 patients were diagnosed as intracranial germinoma. Patients with hCG > 100 IU/l and/or AFP > 10 ng/ml were excluded. Patients, who were diagnosed as germinoma by imaging without histology, were included. RESULTS Follow-up time was from 2 to 467 months (median 136 months). Until 2005, 37 patients were treated with radiotherapy >30 Gy alone or with chemotherapy. After then, 23 patients received whole-ventricle radiotherapy 24-30 Gy with chemotherapy. 2 patients were treated with chemotherapy alone, 3 were unknown. 10-year PFS was 82.05% in radiotherapy >30 Gy alone, 86.36% in radiotherapy >30 Gy with chemotherapy and 100% in radiotherapy 24-30 Gy with chemotherapy. The intracranial adverse events after the initial treatment were identified, such as pituitary dysfunction: 6 (9.2%), hearing disturbance: 2 (3.1%), neurocognitive dysfunction 6 (9.2%), microbleeds 10 (15.4%), cavernous angioma 6 (9.2%), brain tumor 1 (1.5%), cerebral artery stenosis 1 (1.5%). The frequency of late adverse brain events is higher in radiotherapy >30 Gy with/without chemotherapy than 24-30 Gy (total events, 25 vs. 9, P< 0.03). CONCLUSION Patients with intracranial germinoma obtain long-term survival but suffer from the late intracranial adverse events. The late intracranial adverse events occur more frequently in intracranial germinomas treated with radiotherapy >30 Gy than 24-30 Gy. Long-term follow-up is important to promptly identify and deal with the late brain damages.