Background: Comorbidities including dyslipidemia, diabetes and coronary heart disease are frequently found in elderly patients with advanced non-small cell lung cancer (NSCLC). Taking statin and/or metformin attenuates chronic inflammations, and could affect cancer outcomes. We aimed to evaluate prognostic impact of taking statin and/or metformin on survival in elderly patients with advanced NSCLC. Methods: Patients ≥ 70 years with advanced NSCLC incident from 2007 to 2012 were identified using reimbursement claims from Korea’s National Health Insurance Service Database, and exposures to statin and/or metformin were also documented. Cox proportional-hazards model and propensity score matched analysis were used to estimate the impact of drug exposures on overall survival (OS). Results: Excluding 976 treated by upfront anti-EGFR, 7298 receiving palliative chemotherapy were included: statin preparations were taken in 13.0%, metformin preparations in 13.8%, both in 3.5%, and neither in 76.6%, respectively. Median OS of statin + / metformin +, statin + / metformin –, statin - / metformin +, and statin - / metformin – users was 14.5, 12.9, 11.4 and 9.9 months respectively. By multivariate analyses, metformin was not statistically significantly associated with improved OS in statin non-user (HR 0.99; 95% CI 0.91-1.08; p= 0.819) and statin user (HR 0.99; 95% CI 0.85-1.16; p= 0.898) group. However, use of statin, regardless of metformin, was associated with improved OS (HR 0.80; 95% CI 0.74-0.86; p< 0.001). In propensity-matched cohort, survival benefit was noted not by use of metformin (HR 0.97; 95%CI 0.85-1.11; p= 0.661), but by use of statin (HR 0.83; 95%CI 0.73-0.95; p= 0.007). There was no significant effect modifier. Conclusions: We found that the about one-quarter of elderly NSCLC patients were taking statin and/or metformin. Exposures to statin could be the independent prognostic factor for better survival in elderly advanced NSCLC patients.