The aim of this study was to determine the clinical activity and toxicity of a novel chemotherapy regimen of weekly gemcitabine and vinorelbine in patients with advanced non-small cell lung cancer (NSCLC). 40 chemotherapy-naïve patients with stage IIIB/IV NSCLC were included. The doses of gemcitabine and vinorelbine were 1000 and 25 mg/m(2), respectively, given on days 1, 8 and 15, every 28 days. 38 patients were evaluable for response. One patient achieved a complete response (CR) and 10 attained a partial response (PR), for an overall response rate (ORR) of 29% (95% confidence interval (CI): 15-43%). 47% of patients experienced a clinical benefit. The main toxicity consisted of grade 3 anaemia and neutropenia in 5% of patients. Non-haematological toxicity was minimal. The dose-intensities were 744 mg/m(2)/week for gemcitabine and 15 mg/m(2)/week for vinorelbine. 40% of the patients survived for longer than 1 year. The median time to progression was 4 months and the median survival 8.5 months (95% CI: 3.1-13.8 months). The weekly administration of gemcitabine and vinorelbine is very well tolerated and results in an acceptable response rate for the treatment of NSCLC.