The purpose of this study was to evaluate the combination of gemcitabine, paclitaxel, and carboplatin in patients with advanced non-small cell lung cancer. Previously untreated patients with stage IIIB or IV non-small cell lung cancer were enrolled into this trial. Sixty-nine patients from the phase II portion and eight patients from the phase I portion were treated with gemcitabine 1,000 mg/m2 intravenously on days I and 8, paclitaxel 200 mg/m2 as a 1-hour infusion on day 1, and carboplatin at an area under the curve of 5.0 intravenously on day 1. Treatment courses were repeated every 21 days. The phase II component of the study was completed at 13 community-based practices in the Minnie Pearl Cancer Research Network. Thirty-four of 71 fully evaluable patients had an objective response (48%, two complete and 32 partial responses). Twenty-five patients (35%) were stable and 12 (17%) progressed. The median response duration was 6 months (range, 3 to 14 months) and the median survival was 9.9 months, with 1- and 2-year survival rates of 47% and 21%, respectively. The combination of gemcitabine, paclitaxel, and carboplatin has been shown to be safe and effective; thus, this three-drug regimen will be compared with a standard two-drug regimen, paclitaxel/carboplatin, in a phase III study.