Two patients had diffuse, reversible pulmonary injury possibly owing to gold sodium thiomalate treatment: a 32-year-old woman with chronic inflammatory arthritis compatible with seronegative rheumatoid arthritis and a 32-year-old man with shoulder arthralgia. The patients had received 420 mg and 325 mg of gold sodium thiomalate, respectively. Cough and dyspnea began in the seventh and fifth weeks of therapy, respectively. In both patients x-ray study showed bilateral pulmonary infiltrates, with no evidence of pleural disease. The woman had no other manifestations of hypersensitivity to gold. The man had exfoliative dermatitis fever and anemia. Lung biopsies from both patients revealed lymphocytes and plasma cells infiltrating the alveolar septa and interstitial fibrosis. The woman improved slowly during four months after discontinuation of therapy. Pulmonary symptoms recurred after additional gold therapy, and again resolved when gold was discontinued. The man, treated with prednisone, showed prompt remission and remains will without medication.