In order to shed light on the histological changes occurring in the lungs of patients with rheumatoid arthritis (RA), we scrutinized an open lung biopsy file of 199 patients and selected the patients with RA. The histopathological patterns observed were: pulmonary rheumatoid nodules (4 cases, including one with rheumatoid pneumoconiosis); usual interstitial pneumonia (UIP) (2 cases); desquamative interstitial pneumonia (2 cases); bronchiolitis obliterans with patchy organizing pneumonia (2 cases); follicular bronchiolitis (1 case); organizing pneumonia always associated with bronchiolitis (3 cases); granulomatous reaction (3 cases); obliterating vasculitis (3 cases); granulomatous vasculitis (1 case); lymphoid hyperplasia (2 cases); and localized pulmonary fibrosis (1 case). The clinical data and laboratory findings for the histopathological groups overlapped and did not properly predict the anatomical picture. Both patients with UIP died of lung disease. Otherwise the prognosis in the series was good.