To compare the overall survival (OS) of patients with advanced non-small cell lung (NSCLC) treated with either docetaxel plus gemcitabine or single-agent docetaxel. Chemotherapy-naive patients with advanced/metastatic NSCLC were randomly assigned to receive either DG [n=157; gemcitabine 1100mg/m(2) on days 1 and 8], docetaxel 75mg/m(2) on day 8 or D [n=155; docetaxel 100mg/m(2) on day 1] every 3 weeks. A total of 312 patients were evaluable for toxicity and response. A predefined interim intention-to-treat analysis showed significantly longer median OS (p=0.037) in favor of the DG regimen (9.4 months versus 8.3 months for DG and D regimens, respectively), resulting in the premature termination of the study. The DG regimen was also associated with a significantly higher response rate compared to D (26.8% versus 11.6%, p<0.001). TTP were 3.5 and 2.3 months for the DG and D regimen, respectively (p=0.054). Although there were two treatment-related deaths in the DG arm, the toxicity profiles of the two regimens were comparable. The DG regimen was associated with a significantly better quality of life. The efficacy of the docetaxel plus gemcitabine combination is superior to single-agent docetaxel in chemonaive patients with advanced NSCLC.