Chest radiographs were examined in 147 patients with rheumatoid arthritis who were admitted at the Department ofInternal Medicine, Okayama University, Misasa Medical Branch during last ten years. The results were as follows. 1) Diffuse micronodular shadow on chest radiographs was shown in eighty nine out of 147 cases (60.5%), although the incidence of micronodular shadow was 47.3% in the other types except type 1, demonstrating the shadow limitted in the part of lower lung fields. The incidence in type 2 and 3, revealing micronodular shadow distributed over lung fields, was 22.4%. 2) The incidence of micronodular shadow was more frequently found in females than in males. The results obtained here was different from
those previously reported. 3) The cases with type 2 and 3 tended to demonstrate a long duration of the desease, acceleration of ESR, positive rheumatoid factors, and elevation of serum γ-globulin and IgG levels, compared with the other types and cases without radiological findings. 4) Pulmonary lesions induced by treatment of gold or penicillamine were not recognized, except one suspected case with gold therapy.