Objective: To study the toxicities and efficacy of concurrent gemcitabine plus cisplatin combined with three-dimensional conformal radiotherapy for stage Ⅲ non-small cell lung cancer (NSCLC). Methods: Thirty-six patients with pathologically diagnosed NSCLC received radiotherapy and concurrent chemotherapy. There were 22 patients with stage llla and 14 patients with lllb. Radiotherapy was given a total of 60-70 Gy in conventional fractionation. Chemotherapy included gemcitabine (600 mg/m2) and cisplatin (20 mg/m2), once per week. Results: Thirty-two patients received a total dose of 60-72 Gy. Two patients received 56 Gy and another two patients received 58 Gy. Thirty-four patients received 4-6 weeks of chemotherapy, while two patients received only 2 weeks of chemotherapy. The overall response rate (CR + PR), complete response rate (CR), partially response rate (PR) were 63.3% (30/36), 11.1% (4/36) and 72.2% (26/36) respectively. The median follow-up duration was 18.4 months. The 1-and 2-year overall survival rates were 77.8% (28/36) and 55.6% (20/36),respectively. Conclusion: Concurrent gemcitabine and cisplatin combined with three-dimensional conformal radiotherapy for stage Ⅲ non-small cell lung cancer is effective and well tolerated. Lone-term results need further study.