A total of 43 patients with advanced, previously untreated non-small-cell lung cancer (NSCLC) were treated with a novel nitrosourea, fotemustine, given at 100 mg/m 2 on days 1 and 8. Maintenance treatment consisted of a single injection of 100 mg/m 2 given every 21 days. 37 patients were evaluable for response. Of these, 5 patients had a partial response (13.5%; 95% confidence interval, 6%-28%). Toxicity comprised mainly anaemia and thrombocytopenia. Other toxicities were mild. This phase II study confirms that fotemustine is a moderately active and well-tolerated drug in NSCLC.