Eosinophilic granuloma of bone, characteristically a disease of children and young adults, is the most benign variant of histiocytosis X. This benign bone destructive lesion is characterized by the presence of a histiocytic and eosinophilic leukocyte infiltrate of unknown origin. It was described as a new distinct entity by Jaffe and Lichtenstein(1940). we reviewed the ll patients with eosinophilic grnuloma of bone from January 1980 to December 1985. The average length of follow-up was 20 months, with a range of 10 to 38 months. The results were as follows. l. Incidence was 2.24% of primary bone tumor. 2. Male patient was more predominent. 3. Age of onset was between 2 and 16 years old. 4. Predilection sites were spine, skull, pelvis and femur in order. 5. Solitary lesion was more comon(63.5%). 6. Onset of multiple lesions was earlier age. 7. There was on recurrence of lesions.