We aimed to evaluate long-term toxicity in children with medulloblastoma treated with postoperative radiotherapy (RT). This study included 21 patients aged 4-16 who had been diagnosed with medulloblastoma. All of the patients in the study received postoperative craniospinal RT. Postoperative RT followed by chemotherapy was the treatment protocol. A total of 13 patients (62%) received chemotherapy concurrently with RT. Overall survival was 50 months (range, 1-169 months) and disease-free survival was 39 months (range, 4-171 months). In the data analysis, the heights of 11 patients (91.6%) were found to be below 50% on the height curve, and 8 (66.6%) patients had weights below 50% on the weight curve. Mean sitting height was 72.58 ± 6.33 cm, and this was statistically correlated with parameters such as LH level (p=0.037), testosterone level (p=0.020), height (p=0.002), weight (p=0.033) and age at diagnosis (p=0.002). Radiation therapy for medulloblastoma seems to have a late toxic effect on long-term survivors. With the improving survival rate of medulloblastoma patients, RT doses should be as low as possible without sacrificing efficacy.