BACKGROUND: To evaluate the efficacy and safety of gemcitabine and cisplatin chemotherapy in advanced non-small cell lung cancer (NSCLC). MATERIALS AND METHODS: Forty patients (21 men, 19 women ; age range, 37 to 73 years; median, 63 years) with unresectable stage IIIB to IV NSCLC were evaluated. Patients received cisplatin 60mg/m2 (Day 1), gemcitabine 1200mg/m2 (Day 1 and 8) every 21 days. Eighteen patients had stage IIIB disease and 22 had stage IV. There were 28 patients of adenocarcinoma (70.0%), 11 of squamous cell carcinoma (27.5%), and one of large cell carcinoma (2.5%). RESULTS: Of 40 patients, no patients showed complete response while 15(37.5%) showed partial response, 7(17.5%) had stable diseases, 18(45%) had progressive diseases. During a total of 195 courses of chemotherapy, grade 3 or more granulocytopenia and thrombocytopenia occured in 12.5% and 2.5% of patients respectively. Non-hematologic toxicity was mild and easily controlled. There was one case of treatment-related death by pneumomia. The median survival was 55 weeks (95% CI, 34~75weeks), and the time to progression was 19 weeks (95% CI, 16~23weeks). One year survival rate was 55% and 2 year survival rate was 10%. CONCLUSION: The efficacy of cisplatin and gemcitabine combination chemotherapy was acceptable in the treatment of advanced NSCLC.