Ticlopidine-induced lung disease is rare. A 52-year-old man with acute myocardial infarction developed respiratory distress 2 days after receiving ticlopidine for coronary artery stenting. The dosage of ticlopidine was 500 mg orally followed by maintenance of 250 mg twice daily. Chest radiography revealed bilateral haziness predominantly over upper lung fields. He did not respond to treatment for suspected cardiogenic lung edema and mechanical ventilation was instituted. Open lung biopsy documented diffuse alveolar damage. After discontinuing ticlopidine and treatment with systemic corticosteroid, his pulmonary condition improved gradually. Within 2 weeks, the patient was successfully weaned from the ventilator. Although rare, diffuse alveolar damage is a potential side effect of ticlopidine treatment and should be included in the differential diagnoses of heart failure patients taking ticlopidine who respond poorly to optimal therapy.