One hundred and five patients with inoperable non-small cell lung cancer were included in a randomized trial comparing the activity of vindesine as a single agent with the combination of vindesine and cisplatin. All patients were previously untreated and the majority (70%) had squamous carcinoma. The overall partial response rates in 88 evaluable patients were 7% for vindesine alone and 33% for the combined regime. There were no complete responders in either arm. The median survival of patients treated with vindesine and cisplatin was 11 months, compared with 4 months in those treated with vindesine alone (P = 0.008). Patients showing a partial or complete response to vindesine and cisplatin survived a median duration of 13 months, compared with 7 months for non-responders (P = 0.03). This survival benefit associated with the combination was particularly apparent for patients with ECOG performance status 0 or 1 (median survival greater than 18 months and 13 months respectively), locoregional disease (median survival 14 months) and squamous cell histology (median survival 13 months). Myelo-suppression was greater with the combination but was not a major treatment problem. Neurotoxicity, which was frequently dose-limiting, was of similar severity in both treatment groups. The results indicate that the combination of vindesine and cisplatin is superior to vindesine alone for remission induction in non-small cell lung cancer and confers a significant survival advantage compared with vindesine alone in patients with favourable prognostic factors.