In four initial phase II studies of docetaxel administered as a 1-hour intravenous infusion at a dose of 100 mg/m2 every 3 weeks in chemotherapy-naive patients with advanced non-small cell lung cancer (NSCLC), the overall response rate was 31% in 128 evaluable patients and the median survival was 9 months. Five subsequent phase II studies of 100 mg/m2 docetaxel in the first-line setting showed similar results, with response rates in the range of 25% to 63% and favorable survival. Lower doses also have been evaluated in two trials using docetaxel 60 and 75 mg/m2, with overall response rates of 25% and 19%, respectively. In the second-line setting, after failure of first-line platinum-based chemotherapy, four studies of docetaxel 100 mg/m2 have achieved response rates of 16% to 22% and encouraging median durations of survival of 30 to 42 weeks. In both first-and second-line settings, the toxicity of docetaxel is tolerable. Docetaxel is clearly an active drug in both the first- and second-line treatment of NSCLC, and recently conducted phase III trials will further define the role of this agent in the standard treatment of NSCLC.