In 1994, approximately 34,000 to 43,000 Americans will be diagnosed with small cell lung cancer, and 60% to 70% of these individuals will have extensive-stage disease. The median survival time of patients with extensive-stage small cell lung cancer is 8 to 10 months and 10% or less will survive 2 years. There have been no major advances in the treatment of this stage of disease in the past decade. Phase II trials with promising new single-agent chemotherapeutic drugs are justifiable. We report the design and toxicity of a phase II trial with single-agent paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) in previously untreated patients with extensive-stage small cell lung cancer.