The results obtained in this series of 120 patients with brain tumors, excepting hemispheric gliomas, appear particularly comforting. Radiosensitiveness of medulloblastomas, pinealomas and to some extent of ependymomas, was of course known. On the contrary, the radio-sensitiveness of some astrocytary processes, or supposed astrocytomas, well or moderately differentiated (gliomas of the IIIrd. ventricle, opto-chiasmatic gliomas, gliomas of the brain stem) appears to have been appreciable and it has been possible to obtain numerous stabilizations equivalent to cures. An histologic chek-up prior to roentgentherapy appears to authors as strictly necessary and might be easily enough obtained thanks to the stereotaxic procedures. Authors are not of mind that the present series will be burdened with radio-necrotic like complications. They think that the tumoral doses might be increased of 5 p. 100 and even of 10 p. 100, while maintaining the same protraction and a fractioning of the same order: treatments of 5 to seven weeks consisting in 5 to 6 sessions per week). It is presently too soon for valuing the efficiency of an adjuvant chemotherapy.