THE MANAGEMENT of patients at any age with malignant disease is a trying experience for the physician as well as for the patient and his family. When such disorders arise in childhood special problems are presented. Therefore, it occurred to us that observations made during our management of 48 children with leukemia1 and many children with other malignant lesions would be of value to others faced with similar clinical problems. Although many patients in this study were hospitalized for metabolic observations of the effect of folic acid antagonists administered experimentally, we do not imply that prolonged hospitalization is necessary or desirable. Because of the tragic nature of this group of diseases, it is not a simple matter to undertake a carefully controlled study of emotional reactions of either patient or family; it is hoped that some relatively innocuous methods of measurement may be developed and applied in the future.