Histiocytosis syndrome is not rare disease of unknown etiology, characterized by development of granulomatous lesions with histiocytic proliferation. Authors analyzed 22 cases, which had been confirmed as histiocytosis syndrome form 1971 to Feb. 1980 with special attention to 15 cases showing positive findings on radiological examinations. The results are as follows . 1. Overall male to female ratio was about 2 ; 1. The majority were between 1 and 7 years of age. 2. Skeletal system was involved in orders as follows : skull, pelvis, femur, rib, spine. 3. Four cases of pulmonary involvement were experienced, All case had interstitial involvement with reticulonodular densities on roentgenogram. 4. We had experienced a pituitary tumor, presumably localized histiocytic mass, in a patient with diabetes insipidus. 5. In long bone involvement, diaphysis or metaphysis was usually involved, but in one patient, lesions were extended into epiphyiss. 6. One cases of platspondlyly was found , with symmetrical compression.