Childhood cancer is rare, representing only 1% of the total cancer problem. Of children diagnosed with cancer today, more than 70% are predicted to be long-term survivors. Essentially all pediatric cancers are treated by interdigitating radiation with surgical resection and systemic chemotherapy. The use of irradiation, important to achieve high rates of disease local control, must be always balanced against late effects specifically related to this treatment modality, principally growth retardation and second tumors induction. Using neuroblastoma, Wilms' tumor and rhabdomyosarcoma as examples, the advances in the optimal multimodality treatment of childhood cancer and the evolution of the role of radiation therapy are discussed.