Objectives: In the treatment of metastatic RCC, nivolumab has been used with increasing frequency in recent years. Systemic inflammation plays an important role in the initiation and progression of cancer. In this study, we aimed to investigate whether the HALP score, which indicates systemic inflammation, has a predictive significance in patients receiving nivolumab treatment for mRCC. Methods: 45 patients who were treated with nivolumab after first-line anti-angiogenic therapy for mRCC in our clinic and whose files were analyzed retrospectively were included in the study. The cut-off value for the HALP score was calculated using the X-tile software program. Results: HALP score was found to be high (?16.98) in 26 patients and low (<16.98) in 19 patients. Mean progressionfree survival (PFS) was statistically significantly longer in the high HALP group compared to the low group (12.0 months versus 6.0 months). A significant correlation was found between PFS and serum albumin level, while a negative and weak correlation was found between serum LDH levels. Conclusion: We showed that the HALP score is associated with prognosis in patients receiving nivolumab treatment for mRCC. The reliability of this index, which shows systemic inflammation with a low-cost and easily applicable method, should be demonstrated by large-scale studies involving more patients. Keywords: HALP score, nivolumab, progression free survival, renal cell carcinoma.