In the explanatory text of the ILO U/C International classification of Radiographs of Pneumoconiosis (1971) sent to Japan in 1973, items of its expression on pulmonary asbestosis were analyzed by the author. On the other hand, items of Japanese Asbestosis Classification of Pneumoconiosis Law were also analyzed. The ILO U/C International Classification of Radiographs of Pneumoconiosis (1971) have some confused words. As to pulmonary asbestosis, an expression of irregular opacities is used, but the fundamental X-ray opacities such as linear opacities are forgot in the description. The X-ray findings of the pulmonary asbestosis are divided into 3 types as s, t and u. It is, however, difficult in practice to divide X-ray findings of the pulmonary asbestosis into such types. The classification of X-ray findings of the pulmonary asbestosis in the Japanese Pneumoconiosis Law is based on the classification worked out by many investigators i; the past, providing for simplicity and ease of handling.