Pulmonary ventilation was studied on 100 rheumatoid arthritics from a medical outpatient clinic, using wholebody plethysmography, spirography, and pneumometry. Findings were normal in 2/3 of the patients; reduced lung capacity was found in only 3-6%. Thus it is doubtful that significant restriction of ventilation is present in chronic polyarthritis. Nevertheless, 1/4 of all rheumatoid arthritis patients have bronchial obstruction with resulting pulmonary emphysema. Whether or not the incidence of respiratory passage obstruction is directly associated with the underlying rheumatoid disease must await further study.