Non-small cell lung cancer (NSCLC) is usually at advanced stage when it is diagnosed. There is no consensus about the standard treatment in elderly patients with advanced NSCLC. Generally, data regarding elderly patients with NSCLC are withdrawn from general NSCLC studies based on subgroup analyses and suggestions. We evaluated prognostic factors in elderly patients with advanced NSCLC. We reviewed retrospectively 338 patients from August 2005 to July 2009 in two centers in Turkey. Medical records of the patients a parts per thousand yen65 years with advanced NSCLC were collected. Collected data included demographic informations, clinical assessments and information on treatment, toxicities and outcomes. Survival was estimated by using Kaplan-Meier method and prognostic factors were evaluated with log-rank and Cox regression tests. The median overall survival (OS) for the entire group was 15.4 months (95% CI: 12.7-18.0). In univariate analysis, weight loss, stage, combination therapy, second-line chemotherapy and tumor response (P < 0.01) and performance status significantly affected OS (P < 0.05). The median progression-free survival (PFS) was 10 months (95% CI: 8.4-11.6). In univariate analysis, there was only a significant association between tumor response and PFS (14.6 vs. 8.5 months; P < 0.001). Multivariate analysis showed that only response to therapy was an important prognostic factor for OS (P < 0.001). Survival of elderly patients with advanced NSCLC is significantly influenced by performance status, weight loss, stage, combination therapy, second-line chemotherapy and response to therapy. Not only age but also these factors may be kept in mind in the treatment planning of the elderly patients with NSCLC. These results may be of benefit in changing clinical practice in elderly patients with NSCLC who are often undertreated.