Purpose: To determine whether systemic inflammatory response (SIR), particularly platelet-lymphocyte ratio (PLR) and neutrophil-lymphocyte ratio (NLR), has different prognostic role between patients with metastatic renal cell carcinoma (mRCC) receiving first-line tyrosine kinase inhibitors (TKI). Materials and Methods: We retrospectively reviewed 547 patients with mRCC who were diagnosed and treated with a first-line TKI between 2007 and 2015. The primary endpoint was overall survival (OS) and secondary endpoint was progression-free survival (PFS). We evaluated differences in survival outcomes according to SIR and identified predictors of OS and PFS. Results: In synchronous mRCC, patients with a higher PLR had significantly worse OS and PFS. Moreover, a higher NLR was also associated with both worse OS and PFS in these patients. However, PLR was not associated with either OS or PFS in metachronous mRCC patients. While metachronous mRCC patients with a higher NLR had worse OS compared to those with lower NLR, there was no difference in PFS according to the status of NLR. On multivariate analysis, PLR was identified as predictive factor for OS (hazard ratio [HR], 1.55) as well as PFS (HR, 1.39) in patients with synchronous mRCC, but not in patients with metachronous mRCC. Additionally, higher NLR was also remained as predictive factor of both OS (HR, 1.83) and PFS (HR, 1.57) in patients with synchronous mRCC. Conclusions: Our study indicates that simple biomarkers of SIR, particularly PLR and NLR, can be more useful predictors of survival outcomes in patients with synchronous mRCC rather than metachronous mRCC. (Korean