Meta-analysis has demonstrated survival benefit for patients with stage IIIB non-small cell lung cancer treated with sequential chemoradiotherapy versus radiotherapy alone. The introduction of chemotherapy as part of a multimodality approach has improved the outcome in this poor prognostic subset of cancer patients. In the present phase II study we evaluated the safety and activity of a new cisplatin-based three-drug regimen consisting of vinorelbine/ifosfamide/cisplatin (VIP) followed by curative thoracic irradiation in 28 patients with stage IIIB non-small cell lung cancer. Patients received vinorelbine 25 mg/m2 on days 1 and 8, ifosfamide 3 g/m2 on day 1 (with mesna), and cisplatin 80 mg/m2 on day 1 every 3 weeks. After three courses of induction chemotherapy, patients with objective response or stable disease were eligible for thoracic radiotherapy. Twenty-six of the 28 patients received at least three courses of chemotherapy and were evaluable for response. The response rate to induction VIP was 58% (15 of 26 patients; one complete response and 14 partial responses). Seven patients had disease stabilization and four progressed during chemotherapy. Radiation treatment started from 4 to 6 weeks after the end of chemotherapy with standard fractionation (200 cGy/day, 5 fractions/wk/6 wk). Eighteen of 22 patients started thoracic irradiation; 14 completed the treatment plan, reaching the total dose of 60 Gy. The most relevant acute and late toxicities of radiotherapy were grade 3 dysphagia and pneumonitis in two patients and grade 3 lung fibrosis in six patients. By comparing the tumor volumes before and after radiation treatment we observed six clinical remissions, three stable diseases, and five local progressions. The first site of recurrence was local in 10 of 18 patients (56%), distant in seven patients (38.8%), and both local and distant in one patient. Median progression-free survival and overall survival for the patients treated with radiotherapy (18 patients) were 14 months (range, 4 to 36 months) and 26 months (range, 7 to 54+ months), respectively; the 1- and 2-year survival rates were 61% and 52%. Curative thoracic radiotherapy was well tolerated after VIP induction chemotherapy; it reduced residual tumor volume in six patients.