Since Ellman and Ball1first described the occurrence of widespread pulmonary lesions in rheumatoid arthritis, there have been a number of reports of interstitial pulmonary fibrosis in "rheumatoid disease." The purpose of this paper is to report two cases in which pulmonary lesions appeared as significant manifestations of the disease and to record the many unusual features presented by each of these patients. Case 1. —A 67-year-old white woman was admitted to the hospital in January 1958 because of complaints of cough and chest pain of six months' duration and increasing dyspnea for three months. The patient had been in good health most of her life. She was hospitalized 15 years previously for repair of a rectal prolapse, and 5 years previously she had had an episode of herpes zoster. In April 1956, she was admitted to another hospital because of numbness of the left cheek and hands. There