Lung cancer is a leading cause of cancer-related deaths in many countries, including South Korea. As treatment delays after diagnosis may correlate with survival, this study aimed to investigate the association between time-to-treatment and one-and five-year overall mortality in patients aged 60 years or above. Survival analysis using the Cox proportional hazard model were conducted after controlling for all independent variables. Of a total of 1,535 individuals who received surgical treatment due to lung cancer, 837 patients received treatment within 30 days and 698 after 30 days of initial diagnosis. Individuals who received surgical treatment after 30 days of diagnosis were more likely to die within 1-year (Hazard Ratio, HR: 1.15, 95% Confidence Interval, CI: 1.01-1.32) and 5-year (HR: 1.16, 95% CI: 1.02-1.33) compared to those who received treatment within 30 days. The increase in mortality risk with time delay persisted when applying other cut-off times, including standards at 2, 3, and 6 months. We also found that the mortality rate of lung cancer patients differs depending on age (74 years or younger), household income (<80 percentile), patient severity, and the residing region. Our findings show that time delay is an important factor that can influence the outcome of lung cancer patients, highlighting the importance of monitoring and providing appropriate and timely treatment.