The indication for radiotherapy in neuroblastoma depends on the stage of the disease; the irradiation dosage depends on the age of the child. The tumour is radiosensitive, but tends to recur if the irradiation dosage is inadequate. Irradiation of the tumour may induce coversion to a more differentiated tumor pattern. Radiotherapy can reduce the tumour volume, thereby rendering previously inoperable tumours resectable. Since 1959 11 out of 16 children with neuroblastoma undergoing treatment at the Paediatric Department of the University of Vienna were subjected to radiotherapy. Out of 9 children with suprarenal origin of the tumour only one child is still alive (survival time to date-26 months since diagnosis). Out of 7 children with extraadrenal tumour localization 70% have survived for more than 2 years. The side effects of radiotherapy survived for more than 2 years. The side effects of radiotherapy were: 1 case of quadripelgia, 1 case of symmetric growth delay of the pelvis and 1 case of scoliosis.