The antineoplastic activity of vindesine was evaluated in a phase II trial in patients with squamous cell carcinoma, adenocarcinoma and large cell carcinoma of the lung. The following 63 patients participated in the trial: 22 with squamous cell carcinoma, 25 with adenocarcinoma and 16 with large cell carcinoma. Most of the patients had not received prior treatment; 6 had received single-agent chemotherapy. The dose of vindesine was 4 mg/m2 every 2 wk, reduced or increased according to hematologic and neurologic side effects. Fifty-four patients were evaluable. Objective response was observed in 2 of 19 patients with squamous cell carcinoma (11%), in 6 of 22 patients with adenocarcinoma (27%) and in 1 of 13 patients with large cell carcinoma (8%). In patients with adenocarcinoma the median duration of response was 196 days (range, 71-450+). Twenty-five percent of the evaluable patients received .gtoreq. 100% of the scheduled dose. In 39% of the patients, dose reductions were necessary because of leukopenia; in 63%, dose modifications were necessary because of neurotoxic effects. Vindesine as a single-agent chemotherapy evidently is active against adenocarcinoma of the lung. Activity in squamous cell carcinoma and large cell carcinoma appears to be less, but not totally absent.