In order to estimate the influence of radiotherapy on the intellectual development of children with brain tumor, we investigated the educational level of 21 patients with germ cell tumor who had undergone radiotherapy. They were divided into three groups in accordance with their age at the time of radiation; under school age group (under 6 years of age), elementary school age group (from 7 to 12 years of age), and junior high and high school age group (from 13 to 18 years of age). There were 2 cases in the under school age group, one of them graduated from high school and the other is presently a junior high school student. There were 5 cases in the elementary school age group. 3 of these graduated from university, 1 is presently a university student and 1 is a high school student. There were 14 cases in the junior high and high school age group. 2 of these are university students, 7 graduated from high school, 1 is presently a junior high school student, and 4 died because of tumor progression. The mean period of hospitalization of the patients who have been admitted to university was 63.0 days, and that of patients who have not been admitted university was 135 days. There is a statistical difference (p < 0.05). It could be concluded that the period of hospitalization rather than radiotherapy seemed to influence the educational status of children with brain tumor.