Between 1975 and 2005, we treated 52 newly diagnosed germinoma patients. Until 1991, patients with pure germinomas or germinomas with syncytiotrophoblastic giant cells (STGCs) received whole-brain radiotherapy only. Of the 52 patients, 30 were treated with a reduced radiation volume and combined chemotherapy; seven of these received local irradiation with 24 Gy, two received whole-brain (30 Gy) plus local irradiation (20 Gy), 16 received extended local irradiation delivered to the whole ventricles (30 Gy) plus local (20 Gy) irradiation, and five received extended local irradiation (24 Gy). Of the 30 patients treated with a reduced radiation volume and combined chemotherapy, four experienced tumor recurrence; three patients had been treated with 24 Gy of local radiotherapy and one had received extended local (30 Gy) plus local (20 Gy) irradiation in addition to chemotherapy. In these patients, the delivered radiotherapy was inadequate and the origin of the recurrent tumors was outside the radiation field. None of the patients who had received at least 24 Gy of whole ventricle radiotherapy combined with chemotherapy experienced tumor recurrence. In combination with chemotherapy, the delivery of irradiation covering the ventricles effectively reduced the incidence of tumor recurrence in patients with germinomas or germinomas with STGCs.