Neutrophil to lymphocyte ratio (NLR) has been shown to be a prognosis indicator in different types of cancer. We aimed to investigate the association between NLR and therapy response, progression free survival (PFS) and overall survival (OS) in advanced non-small cell lung cancer (NSCLC) patients treated with first-line platinum-based chemotherapy. Patients who were hospitalized between January 2007 and December 2010 were enrolled and eliminated according to the inclusion and exclusion criteria. The NLR was defined as the absolute neutrophil count divided by the absolute lymphocyte count. Logistic regression analysis was applied for response rate and Cox regression analysis was adopted for PFS and OS. A P value of ≤0.05 was considered to be statistically significant. A total of 182 patients were enrolled in the current study. The median PFS was 164.5 days and median OS was 439.5 days. The statistical analysis data indicated that low pretreatment NLR (≤ 2.63) (OR = 2.043, P = 0.043), decreased posttreatment NLR (OR = 2.368, P = 0.013), well and moderate differentiation (OR = 2.773, P = 0.021) and normal CEA level (≤ 9.6 ng/ml) (OR = 2.090, P = 0.046) were associated with response to first-line platinum-based chemotherapy. A high pretreatment NLR (HR = 1.807, P = 0.018 for PFS, HR = 1.761, P = 0.020 for OS) and distant metastasis (HR = 2.118, P = 0.008 for PFS, HR = 2.753, P = 0.000 for OS) were independent prognostic factors for PFS and OS. Elevated pretreatment NLR might be a potential biomarker of worse response to first-line platinum-based chemotherapy and shorter PFS and OS for advanced NSCLC patients. To confirm these findings, larger, prospective and randomized studies are needed.