The aim of this study was to assess the activity and toxicity of carboplatin/vinorelbine combination chemotherapy in unresectable locally advanced and metastatic non-small cell lung cancer. Between April 1997 and June 1999 30 patients (22 M, eight F, median age 62) received treatment with carboplatin AUC 6 on day 1, and vinorelbine 25mg/m(2) on days 1, 8 and 15. Treatment was given every 28 days for six cycles unless progressive disease occurred. Twenty-three patients (77%) had stage IV disease, and seven (23%) stage IIIB. Ninety-three percent were WHO performance status 0-1. Twenty-three patients were fully assessable. Nine patients achieved partial responses (9/23, 39%) for an overall objective response rate of 9/30 (30%; 95% CI 15-49%). The median duration of response was 2.75 months (range 1-13 months). The median progression-free survival was 2 months and the median survival 5.25 months. The actuarial 1-year survival was 20%. The median number of cycles completed was two (range 1-6). Day 15 vinorelbine was administered in only 18% of cycles. The main toxicity was myelosuppression. WHO grade III/IV neutropenia was experienced in 50% of patients, however, there were only three episodes of febrile neutropenia. Eight patients required blood transfusion and one developed grade III thrombocytopenia. Treatment was ceased in one patient because of grade IV autonomic neuropathy. No patient had significant nausea and vomiting. There were no treatment-related deaths. These results indicate that carboplatin/vinorelbine is well tolerated and has similar activity to cisplatin/vinorelbine in patients with unresectable non-small cell lung cancer, however, the median survival was considerably shorter.