We analyzed the chest CT findings in nine patients with biopsy-proven eosinophilic granuloma. Multiple cystic lesions with relatively thin walls seems characteristic of this disease. Small nodular lesions and increased density were observed in many cases. Pleural or subpleural lesions were found in all cases. In seven cases, the distribution of the lesions were predominantly in the upper or upper and middle lung fields. In the remaining two cases however, lesions were found homogeneously throughout the whole lung. In order to analyze the site of the lesions in the secondary pulmonary lobule, a specimen obtained from an open lung biopsy was inflated and fixed using fixative by Heitzman's method. Observation of the slices of the specimen by dissection microscope and their soft X-ray radiographs demonstrated that the lesion existed in the central area of acini. However, CT of the patient before open lung biopsy didn't showed centriacinar distribution. The disparity is because a certain number of lesions lobule is necessary to identify the centriacinar pattern by CT.