Background: We assessed the impact of gene polymorphisms on clinical outcome in advanced non-small cell lung cancer (NSCLC) patients receiving platinum-gemcitabine chemotherapy (PG). Methods: 137 patients with stage IIIB/IV NSCLC receiving first-line PG chemotherapy (cisplatin in 74%, carboplatin in 26% of patients) were included. Mutations in 15 genes were analyzed from peripheral blood, and genotypes were compared with progression-free survival (PFS), objective response rate (ORR), overall survival (OS) and toxicity. Results: Median PFS was 5.8 months, median OS 10.2 months; 44 patients (32%) had a partial treatment response. In the adjusted model, carriers of the ERCC1 T-allele had a lower PFS compared to carriers of the CC-genotype (HR 1.62, 95%, p=0.05). Carriers of the ERCC1 CC-genotype had a higher ORR compared to carriers of the T-allele (52% vs. 29%, p=0.02). The GSTP1 GG-genotype was associated with severe platinum-associated polyneuropathy (p=0.01). ERCC1 (HR 1.54, 95% CI 1.00-2.39, p=0.05), XPD10 (HR 0.64, 95% CI 0.42-0.98, p=0.04) and XRCC1 (HR 0.51, 95% CI 0.29-0.91, p=0.02) were independently associated with OS. Conclusions: This study supports the potential predictive value of the ERCC1, XRCC1 and XPD10 germline polymorphisms in patients with advanced NSCLC receiving platinum-based chemotherapy. Non platinum-containing chemotherapy in carriers of the ERCC1 T-allele, the XRCC1 A-allele and the XPD10 G-allele may be considered and could be subject of further studies.