Introduction:To evaluate the efficacy and tolerability of gefitinib (Iressa (ZD 1839); Astrazeneca, Willington, DE), a novel epidermal growth factor receptor tyrosine kinase inhibitor, in patients with pretreated advanced non-small cell lung cancer (NSCLC). Materials and Methods: Patients with pretreated advanced NSCLC received gefitinib at a daily dose of 250 mg orally until disease progression. Patients included in this study all had measurable, locally advanced or metastatic NSCLC, pretreated with at least one line of platinum based chemotherapy. Results: From June 2004 to February 2006, 18 consecutive patients were enrolled onto the study, the overall disease control rate was 66.7% (partial response (PR), 11.1%; stable disease (SD) 55.6%), median TTP was 2.9 months (95% confidence interval 2.3 to 3.2 months) and median PFS was 3 months (95% confidence interval 2.4 to 3.6 months), median OS from start of gefitinib was 8.4 months (95% confidence interval 5 to 11.8 months). Univariete analysis of prognostic factors revealed that, response to gefitinib and longer duration of gefitinib treatment showed a better PFS, while only longer duration of gefitinib treatment showed a better OS. Conclusion: Gefitinib showed clinically meaningful anti-tumor activity and provided symptom relief as second and third line treatment in pre-treated advanced NSCLC. Gefitinib is tolerable and had favorable adverse events.