Neurofibromatosis is a systemic hereditary disorder with varied manifestations in bone, soft tissue, the nervous system, and skin. Neurofibromatosis is characterized by cafe au lait macules, neurofi- bromas, Lisch nodules, optic gliomas, bony dysplasia, intertriginous freckling, and autosomal inheritance. Juvenile xanthogranuloma(JXG) is a benign, self-healing disorder of infants, children, and occa- sionally adults, characterized by yellowish papulonodular lesions located in the skin and other organs and consisting of an infiltrate of histiocytes with a progressively greater degree of lipidation in the absence of metabolic disorders. In 1954 Normland reported the first case of a JXG in a child with numerous cafe au lait macules. Royer, in 1958, reported the triple association of JXG, neurofibromatosis, and leukemia. It is estimated that children with neurofibromatosis and JXG have a higher risk for leukemia than do patients with neurofibromatosis who do not have JXG. In patients with both JXG and neurofibromatosis, long-term follow-up is required because of the additional association with leukemia. We report a case of JXG associated with neurofibromatosis. (Korean J Dermatol 1998;36(1): 129-132)