Background: This trial investigated the activity and toxicity of gemcitabine in previously untreated elderly (>70 years) patients with advanced (stage IIIB-IV) non-small cell lung cancer (NSCLC). Patients and methods: From January 1997 to July 1998, 46 patients with advanced NSCLC aged over 70 years with a performance status of 0–2 were entered into the study. Gemcitabine 1000 mg/m² was administered as a 30-min infusion once a week for 3 weeks followed by a week of rest; cycles were repeated every 4 weeks. Results: Forty-four patients were evaluable for response. One complete response and nine partial responses were observed, for an overall response rate of 22.2 % (95 % C.I.: 11.3–37.5). The median time to disease progression was 5.1 months (95 % C.I.: 3.5–6.7), the median duration of response was 6.3 months, and the median overall survival time 6.75 months (95 % C.I.: 5.3–8.2). All patients were evaluable for toxicity (184 cycles, median=3 cycles/patient) and no grade 4 hematologic toxicities were reported. WHO grade 3 leukopenia, neutropenia and anemia occurred in 3.3, 0.5 and 1.1 % of cycles, respectively. Grade 3 skin rash occurred in 4.3 % of patients. These side effects led to treatment discontinuation in two patients. Conclusion: Our data show that gemcitabine is active and well tolerated in patients aged over 70 years with advanced NSCLC.