Background: Lung Cancer is the leading cause of cancer related deaths in the USA. NSCLC comprises about 85% of lung cancer cases. Although timeliness of care in patients with NSCLC is considered an important aspect of quality care, there are conflicting data about its impact on clinical outcomes. The primary objective of this study is to determine if there is an association between TTI and survival in patients with NSCLC. Methods: In this retrospective study, we reviewed data from our multi-site Mayo Clinic Cancer Center registry and identified patients with newly diagnosed NSCLC from 2000 to 2016. TTI was calculated from time of diagnosis to time of first treatment (surgery, radiation therapy or systemic therapy). Analyses were performed by SAS software 9.4. Log-Rank test was used to compare survival. Cox regression multivariate model was used to evaluate the prognostic value of variables to survival. Results: 10010 patients (53% males and 47%) were reviewed. Median age at diagnosis was 70. Median TTI was 12 days for stage I, and 20 days for stage II, III and IV. We compared outcomes of patients with TTI > 20 days to TTI ≤20 days. Outcomes were stratified based on age, gender, grade, and stage. Median Overall Survival (OS) was significantly better for patients with TTI ≤20 days compared to TTI > 20 days (39.1 vs 28.6 months P-value < 0.0001). Further stratification, based on stage, showed significantly better OS for stage I and II patients with TTI ≤20 days compared to TTI > 20 days (103.4 vs. 63.9 months P-value < 0.0001 and 72.3 vs. 46.8 months P-value 0.0014 respectively). OS for stage III patients with TTI ≤20 days was not significantly different from patients with TTI > 20 days (30.6 vs. 28.5 months P-value 0.118). Interestingly, stage IV patients had worse OS if TTI ≤20 days compared to TTI > 20 days (8.3 vs. 12.8 months P-value < 0.0001). Conclusions: Our study showed an association between TTI and survival of patients with NSCLC. Shorter TTI was associated with better survival in stage I and II patients and worse survival in stage IV patients. Our study further highlights the controversy surrounding the topic of impact of timeliness of care on survival in patients with cancer, specifically NSCLC across different stages.