ZD1839 is an orally active inhibitor selective for the epidermal growth factor receptor tyrosine kinase and has shown promise in the treatment of non-small cell lung cancer (NSCLC). We now present a case of diffuse alveolar damage (DAD) that developed in a 67-year-old man treated with ZD1839. On day 8 of ZD1839 administration, the patient complained of dyspnea and a new-ground glass opacity was apparent on a chest X-ray and computed tomography scan. Despite high-dose steroid therapy, the patient died 13 days after the first administration of ZD1839. Postmortem analysis of lung tissue revealed a pattern of DAD. No evidence of infection or of other specific etiologies was apparent. This case is the first reported of respiratory failure after ZD1839 treatment in a patient with NSCLC. Physicians should therefore be aware of the potential pulmonary toxicity of ZD1839.