Between 1976 and 1988, 17 patients suffering from tumours located in the third ventricular region were entered into a retrospective study. There were 11 males and 6 females aged from 2 to 30. These tumours were located in the pineal area (n = 12), in the floor of the third ventricle (n = 3), in the roof of the third ventricle (n = 1) and multiple midline tumours (n = 1). A ventriculoperitoneal shunt was performed in 13 patients. In 8 patients the tumour was operated upon directly. 2 patients did not undergo surgery. A histological examination was performed in 13 cases with identification of 9 germinomas, 2 pinealoblastomas and one astrocytoma. In one case the plasma and cerebro-spinal-fluid level of tumour markers (human béta chorionic gonadotrophin & alpha feto protein) were elevated. All patients received 45 to 60 grays by cobalt megavoltage irradiation on the tumoural volume, 8 of them receiving additional whole brain and spinal irradiation ranging from 30 to 36 grays. One patient had chemotherapy in addition to radiotherapy. The 5 years survival rate was 74% and the mean follow-up period was 5 years. Five deaths occurred: 1 during irradiation, 3 following a relapse and 1 unexplained death later on. There were no neurological sequelae related to irradiation but 7 patients (37%) had pituitary insufficiency. The irradiation dose level required to obtain local control, the methods of spinal prophylactic treatment and the role of chemotherapy are discussed.