A group of 56 patients who had received sustained, systemic corticosteroid therapy were examined in order to determine the incidence of posterior subcapsular cataracts. Thirty-eight of the patients were rheumatoid arthritics, while 12 received corticosteroids because of bronchial asthma, 5 for systemic lupus erythematosus, and 1 for dermatomyositis. Fourteen patients out of the group of 38 (37%) rheumatoid arthritics exhibited the characteristic posterior subcapsular cataracts while a control group of 24 arthritic patients failed to show similar lens changes. Two patients in the group of 12 (17%) asthmatics also demonstrated posterior subcapsular cataracts. The dosage and duration of systemic corticosteroid administration appeared to be the major determining factor in the production of the lens changes.