The efficacy and safety of paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) administered as a 3-hour infusion was investigated in a phase II study involving 21 patients with stage III/IV non-small cell lung cancer. The study included two quality of life assessments (the Hospital Anxiety and Depression Scale and the Rotterdam Symptom Checklist) to test their suitability for use in a future randomized phase III trial of paclitaxel and best supportive care versus best supportive care alone. Four (19%) of the 21 patients (95% confidence interval, 8% to 38%) achieved a partial response. The median time to disease progression for all patients entered was 19 weeks. Paclitaxel was well tolerated, with dose reduction required in only one patient because of arthralgia/myalgia. No dose reductions, delays, or discontinuations were required for hematologic toxicity. Completion and compliance with quality of life questionnaires was high, and these research tools proved to be acceptable for future use in phase III studies with paclitaxel.