During treatment with cortisone or corticotropin (ACTH) of patients with rheumatoid arthritis, most of the clinical features that have been described in Cushing's syndrome have been encountered, and it has been anticipated that the osteoporosis and fractures characteristic of this disorder would become manifest in patients sustained on hormonal therapy over long periods of time. Since some degree of osteoporosis is common in patients with chronic rheumatoid arthritis and because it is difficult to make accurate comparative studies owing to variations in radiological technique, it has not been possible in most instances to appraise the possible progression of osteoporosis resulting from treatment withcorticotropin or cortisone. It might be expected in severe rheumatoid arthritis with marked osteoporosis that fractures would occur frequently, but actually it is one of the rarer complications of the disease.1The development, however, of pathological fractures in five patients who received hormonal therapy for periods