Authors analyzed 21 cases of CT findings of radiation-induced pulmonary injury. Alveolar consoliation and partial fibrotic change of the irradiated field were early manifestation followed by total fibrotic change, atelectatic change and bronchiectasis. The most common finding was fibrotic change (15 cases). Early appearance and augmentation of pulmonary injury were noted in combined chemotherapy. CT is useful for the detection of subtlechange of early radiation pneumonitis and for the evaluation of the large area of increased density within their radiated field on plain chest radiograph.