Objectives: Elderly carry a disproportionate burden of lung cancer in the US. Therefore, its important to ensure that these patients receive quality cancer care. Timeliness of care is an important dimension of cancer care quality but its impact on prognosis remains to be explored. This study evaluates the variations in guideline-concordant timely lung cancer care and prognosis among elderly in the US. Materials and methods: Using the Surveillance, Epidemiology, and End Results (SEER)-Medicare database (2002-2007), we identified elderly patients with lung cancer (n=48,850) and determined time to diagnosis and treatment. We categorized patients by receipt of timely care using guidelines from the British Thoracic Society and the RAND Corporation. Hierarchical generalized logistic model was constructed to identify variables associated with receipt of timely care. Kaplan-Meier analysis and Log Rank test was used for estimation and comparison of the three-year survival. Multivariable Cox proportional hazards model was constructed to estimate lung cancer mortality risk associated with receipt of delayed care. Results: Time to diagnosis and treatment varied significantly among the elderly. However, majority of them (77.5%) received guideline-concordant timely lung cancer care. The likelihood of receiving timely care significantly decreased with NSCLC disease, early stage diagnosis, increasing age, non-white race, higher comorbidity score, and lower income. Paradoxically, survival outcomes were significantly worse among patients receiving timely care. Adjusted lung cancer mortality risk was also significantly lower among patients receiving delayed care, relative to those receiving timely care (Hazard ratio (HR)=0.68, 95% Confidence interval (CI)=(0.66-0.71); p≤ 0.05). Conclusion: This study highlights the critical need to address disparities in receipt of guideline-concordant timely lung cancer care among elderly. Although timely care was not associated with better prognosis in this study, any delays in diagnosis and treatment should be avoided, as it may increase the risk of disease progression and psychological stress in patients. Furthermore, given that lung cancer diagnostic and management services are covered under the Medicare program, observed delays in care among Medicare beneficiaries is also a cause for concern.