BACKGROUND: Lung cancer is the leading cause of cancer deaths in Korea and the number of lung cancer deaths is increasing. The higher response rates, decreased toxicity and improved performance status of the first-line treatments have resulted in an increased number of patients becoming candidates for second-line therapy. Several new anti??neoplastic agents, including gemcitabine, docetaxel and paclitaxel, have recently demonstrated second-line activity. This phase II study evaluated the efficacy and toxicity of gemcitabine and vinorelbine as combination chemotherapy for Korean patients with NSCLC as a second-line treatment. METHODS: Sixty response-evaluable patients were enrolled from December 2000 to July 2003. We conducted a phase II study of a combination gemcitabine and vinorelbine chemotherapy for patients with histologically confirmed NSCLC that was stage IIIB and IV disease at the time of diagnosis, and the disease had progressed onward or the patients had relapsed after first-line platinum-based chemotherapy. They were treated with intravenous gemcitabine 1000mg/m2 and intravenous vinorelbine 25mg/m2 on days 1 and 8. This chemotherapy regimen was repeated every 3 weeks. RESULTS: A total of 215 cycles of treatment were given and the mean number of cycles was 3.6 cycles. All the patients were evaluable for the toxicity profile. The response rate was 10% according to the WHO criteria.?The median progression free survival was 3.8 months and the median survival time was 10.1 months. The 1-year survival rate was 32.9%. Grade III and IV neutropenia were seen in 20 (33.3%) and 7 (11.7%) patients, respectively. CONCLUSION: The combination of gemcitabine and vinorelbine is active and well tolerated as a second-line therapy for patients with advanced nonsmall cell lung carcinoma.