Gefitinib (Iressa, 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). There has been no report to date of the effect of gefitinib treatment in patients with small-cell lung cancer (SCLC). Here we report a case of metastatic SCLC that was successfully treated with gefitinib. This case is the first reported of objective clinical response after gefitinib treatment in a patient with SCLC. Our report suggests that treatment with gefitinib is a novel option for a subset of patients with SCLC.