Ten well-nourished children with acute non-lymphocytic leukemia (ANLL) were randomly assigned to groups that received (a) total parenteral nutrition (TPN) throughout the period of induction therapy or (b) standard nutritional support. Body mass and skin hypersensitivity reactions were better maintained in experimental patients. Patients on TPN had higher total white blood counts, absolute granulocyte counts, and platelet counts than did control patients during the course. No difference was apparent in the frequency of febrile episodes, or other aspects of the patients' courses. This preliminary report suggests that intensive nutritional support may accelerate the recovery of normal marrow function during induction therapy for ANLL.