Introduction and aim To investigate the effect of the prognostic nutritional index on treatment response and survival in patients with metastatic renal cell cancer. Methods We retrospectively analyzed the treatment modalities; the demographic, clinical and pathological features of 396 patients with RCC and prognostic nutritional index. Based on the median value, patients were grouped as having low and high prognostic nutritional index values. Kaplan-Meier method was used for survival analysis, and Cox-regression analysis was used for multivariate analysis. Results The median overall survival was 39 months (95% CI 26.1-51.8), 28 months (95% CI 17.9-38) and 7 months (95% CI 4.7-9.2) in patients with favorable, intermediate and poor International Metastatic Renal Cell Carcinoma Database Consortium risk group, respectively. The difference between the groups was statistically significant (p < 0001). Overall survival was 11 months (95% CI 7.5-14.5) in the low-prognostic nutritional index (prognostic nutritional index <= 38.5) group, and 41 months (95% CI 30.5-51.4) in the high prognostic nutritional index (prognostic nutritional index >38.5) group (p < 0.001). In Cox regression analysis, Eastern Cooperative Oncology Group performance score (HR: 2.5), time to systemic treatment (HR: 1.7) and prognostic nutritional index (HR: 1.8) were associated with overall survival. Conclusion In patients with renal cell cancer, prognostic nutritional index is closely related to survival and has prognostic significance.