Eosinophilic granuloma of bone is a self-limited condition, characteristically a disease of children and young adults. It is the most benign variant of histiocytosis X. It is most common in skull, but any bone may be affected. Vertebral involvement occurs in about 10 to 15%. This benign bone destructive lesion is characterized by the presence of Langerhans cells contain Birbeck granules, infilitration of histiocytes and eosinophilic leukocytes unknown origin. We report a eosinophilic granuloma in lumbar spine of old patient.