OBJECTIVE This study aimed to explore the prognostic value of preoperative red blood cell distribution width (RDW) in patients with metastatic renal cell carcinoma (mRCC). METHODS Clinicopathological data of 230 patients with mRCC treated at the First Affiliated Hospital of Chongqing Medical University and the Chinese PLA General Hospital from January 2008 to December 2018 were retrospectively analyzed. Patients were stratified according to the optimal cut-off value of RDW calculated using X-tile software. The prognostic value of RDW was analyzed using the Kaplan-Meier curve with log-rank test and univariate and multivariate Cox proportional hazards models. RESULTS A total of 230 patients were included. The optimal cut-off value of RDW obtained using X-tile software was 13.1%. The median Progression-free survival (PFS) and Overall survival (OS) of all populations were 12.06 months (IQR: 4.73-36.9) and 32.20 months (IQR: 13.73-69.46), respectively. Kaplan-Meier curves showed that patients with high RDW had worse PFS and OS than those with low RDW (median PFS of 9.7 months vs. 17.9 months, P = 0.002, and median OS of 27.8 months vs. 45.1 months, P = 0.012, respectively). Multivariate analysis showed that RDW was an independent risk factor for PFS (HR: 1.505; 95% CI: 1.111-2.037; P = 0.008) and OS (HR: 1.626; 95% CI: 1.164-2.272; P = 0.004) in mRCC after cytoreductive nephrectomy. CONCLUSIONS Preoperative RDW was independently associated with PFS and OS in patients with mRCC and may be a potential predictor of survival outcomes in mRCC.