We initiated a phase II pilot study to determine whether adding paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) to combination carboplatin/etoposide is tolerable and active in patients with advanced non-small cell lung cancer and extensive small cell lung cancer. Patients were given carboplatin (area under the concentration-time curve of 6) followed by etoposide 80 to 100 mg/m2 intravenously on days 1 through 3 followed by paclitaxel 200 mg/m2 intravenously over 3 hours on day 3. On days 4 through 18, granulocyte colony-stimulating factor 5 microg/kg was administered subcutaneously. Each cycle was repeated every 21 days. Fourteen patients have been accrued to the study and 12 were evaluated for toxicity, the first 10 of whom were treated with 80 mg/m2 etoposide. Among the first 10 evaluable patients, significant grade 4 neutropenia occurred in one patient, grade 4 thrombocytopenia in three patients, grade 2 neuropathy in two patients, and grade 3 neurotoxicity in two patients. None of the four patients with non-small cell lung cancer responded to treatment, while six of seven small cell lung cancer patients have obtained major responses to therapy. We have increased the etoposide dose to 100 mg/m2 in subsequent patients. The combination chemotherapy regimen of carboplatin, etoposide, and paclitaxel is tolerable and active in patients with small cell lung cancer.