The prognosis of children with neuroblastoma has shown remarkable improvement in recent years. All of the early reports emphasized the rapid course and fatal termination. Farber (5), in 1940, was the first to report that cures could be obtained. Despite the bizarre natural history of this neoplasm, which includes spontaneous regression (2, 7, 22) and maturation into a more differentiated benign form (11, 19, 25), we feel that the improved outlook is due chiefly to the intelligent use of x-ray therapy. Although surgical excision may be curative when no distant metastases are present (1, 10, 15), frequently the tumor is unresectable, so that only biopsy or partial removal is feasible (13, 18). Thus, one must rely in most instances upon radiation therapy as the chief therapeutic agent. During the interval from July 1949 to July 1955, 19 patients with neuroblastoma were treated at the Mallinckrodt Institute of Radiology. All patients referred for radiotherapy were accepted for treatment, and in all the diagno...