Weekly vinorelbine injection with cisplatin had been used in treatment of non-small-cell lung cancer. We performed a phase II trial to evaluate the efficacy and toxicity of a new schedule of vinorelbine and cisplatin in patients with previously untreated, inoperable (stage IIIB or stage IV) non-small-cell lung cancer. From April 1996 to May 1997, 52 patients were enrolled for study, and 50 patients were eligible and evaluable for both response and toxicity assessment. Therapy consisted of vinorelbine, 30 mg/m2, intravenously on days 1 and 5 of a 21-day cycle, and cisplatin 100 mg/m2 (reduced to 80 mg/m2 after the first seven patients) given on day 1. A total of 211 treatment courses were administered; the median number of cycles administered per patient was 4.5 (range: 1-6), the median dose intensity for vinorelbine was 16.9 mg/m2/week (84.4%), whereas that of cisplatin was 22.8 mg/m2/week (84.7%). Twenty-five patients responded to therapy for an overall response rate of 50%; one patient attained a complete response (2%). The main toxicities were vomiting, myelosuppression, and diarrhea, which included World Health Organization grade 3 or 4 nausea/vomiting (58% patients), anemia (41% patients), neutropenia (12% patients), and diarrhea (14%). The median duration of responses was 9 months. The median time to disease progression was 6.8 months (range 0.4-18.1 months). Median survival was 13 months, and 54% of patients were alive at 1 year. We conclude that this new schedule of vinorelbine and cisplatin achieves a high response with acceptable toxicity profile in patients with advanced non-small-cell lung cancer.