Objective: We observe the curative effect, median survival time, time to progression, quality of life and adverse effect of patients with advanced refractory non-small cell lung cancer (NSCLC) after gefitinib (Iressa) treatment. Methods: Forty-one patients with grade IIIb to IV NSCLC previously treated with two chemotherapy including 85.4% of patients after second line therapy were chosen. The regimen was oral intake of gefitinib 250 mg once daily until the disease progression or toxic reaction has become intolerable. The patients were required to receive tumor evaluation before the treatment, one month, two month and every three months after Iressa administration. Results: All of 41 patients were evaluable for thera-peutic effect. Without complete regression being observed, partial response rate (PR), stable disease (SD) and progression of disease (PD) were 43.9% (18/41), 34.1% (14/41) and 22.1% (9/41), respectively. The overall response rate was 43.9% (18/41) and disease control rate (PR + SD) was 78% (32/41). The response rate in male was 42.1%, while it in female was 45.5% (P > 0.05). Twenty-two of them (53.7%, 22/41) were still alive with 10.1 months of MST when the follow-up ended in November 2006. TTP and MST of patients who died was 2.7 and 5.0 months, respectively. The rate of symptom improvement was 78% of all patients with 13 months of MST of PR patients. The Kamofsky enhanced 20 + 5 after 28 days treatment without 3-4 degree of reactive toxicity. Conclusion: Iressa has significant antitumor activity in advanced NSCLC patients who have previously failed in second or third line chemotherapy. Iressa is effective and safe for patients with poor performance status.