Aim of this study was to estimate efficacy of gemcitabine in first and the second-line chemotherapy for patients with advanced non-small cell lung cancer (stage III and IV). In first-line chemotherapy, 120 patients were treated with different chemotherapy regimens. Fifty-nine patients were treated with gemcitabine / cisplatin (PG), 41 with cisplatin / etoposide (PE) and 20 with mitomycin / ifosfamide / cisplatin (MIC). Forty patients, unsuccessfully treated with PE and MIC in first-line therapy were treated with PG (24 pts) and with best supportive care (BSC) (16 pts). In first-line therapy PG was superior to PE and MIC protocol (mean survival (MS) 10 vs. 7 vs. 8.5 months). Response rate (RR) for PG in first-line therapy was 46% and 21% in second-line. We showed also significantly better survival in patients treated with PG in second-line chemotherapy comparing to best supportive care (MS 9 vs. 5.5 months). Toxic side effects for combination PG was acceptable. This study confirmed that PG combination is safe and effective as first and second-line chemotherapy for patients with advanced non-small cell lung cancer.