Programmed death ligand 1 (PD-L1) is an immunosuppressive membrane protein which, when interacting with its receptor programmed death 1 (PD-1), acts as a negative regulator of the anti-tumor T cell-mediated immune response. Overexpression of PD-L1 in different malignancies such as melanoma and gastric cancer is associated with poor clinical outcomes. The prognostic value of PD-L1 expression in renal cell carcinoma (RCC) has been controversial to some extent. In this study, the prognostic value of PD-L1 expression in RCC was evaluated by analyzing PD-L1 immunoreactivity in tumor cells and tumor infiltrating immune cells (TIICs) in 358 RCC patients with long term follow-up. Since the discrepancy between previous studies may be due to the lack of standardized methodology for evaluating PD-L1 expression by immunohistochemistry, the agreement between two anti-PD-L1 antibody clones, 28.8 and SP142, was also compared. PD-L1 positivity in tumor cells was associated with higher Fuhrman nuclear grade (p<0.001), recurrence (p=0.006), and death due to RCC (p=0.05). PD-L1 positivity in TIICs was associated with higher Fuhrman grade (p<0.001), higher AJCC-stage (p=0.019), and death due to RCC (p=0.001). A multivariate regression analysis revealed a significant positive association of time to cancer-specific death with both PD-L1 positive tumor cells and TIICs (p= 0.014 and p= 0.004, respectively). To conclude, RCC patients with PD-L1 positive tumor cells and TIICs are at significant risk for cancer progression, and the expression of PD-L1 on those cell types may be used as a complementary prognostic factor in the management of RCC patients.