Gefitinib (Iressa), the first commercially available epidermal growth factor receptor-tyrosine kinase (EGFR-TK) inhibitor, is indicated in the management of patients with locally advanced or metastatic non-small-cell lung cancer (NSCLC). However, approved uses differ between countries; in most markets, gefitinib is approved for third-line use only (e.g. the US, Canada and Switzerland), although in some it is approved for both second- and third-line use (e.g. Japan and Australia) and, additionally, in patients considered unsuitable for chemotherapy (e.g. Indonesia and the Philippines). Few third-line treatment options exist for patients with inoperable advanced NSCLC who have failed both platinum-based and docetaxel chemotherapies. Gefitinib represents a significant advance in the treatment of this population; a once-daily, oral dosage of 250 mg/day was well tolerated, produced objective tumour responses and disease stabilisation, and improved disease-related symptoms and quality of life. It also produced overall survival outcomes that compared favourably with historical outcomes in a similar group of patients treated with three or four different chemotherapy regimens. These findings have been supported by observations from a global compassionate-use programme. Ongoing or planned clinical trials are designed to confirm and/or further define the role of the drug in the above and other clinical settings.