Eg5 is a member of the kinesin family of proteins, which associates with bipolar spindle formation in dividing tumor cells during mitosis. The aim of our study is to investigate the prognostic role of Eg5 expression in patients with renal cell carcinoma (RCC). RCC tissue specimens from 164 consecutively treated patients who underwent surgery between 2005 and 2011 were evaluated. The Eg5 expression was determined by immunohistochemistry, and correlated with clinicopathological parameters. The prognostic significance of Eg5 expression was explored using the univariate and multivariate survival analysis of 164 patients who were followed; one hundred and sixty-four tissue specimens "of patients" who were regularly followed with the mean 35.8 months (from 5 to 80 months). The expression of Eg5 was significantly associated with tumor nuclear grade (P = 0.019) and stage (P = 0.007), as well as tumor size (P = 0.033). In univariate analysis, Eg5 overexpression showed unfavorable influence on recurrence-free survival with statistical significance (P = 0.003). Clinical stage, nuclear grade and tumor size also showed strong statistical relation with adverse recurrence-free survival (P < 0.001). Multivariate analysis revealed that tumor stage, nuclear grade and Eg5 reactivity (P < 0.001, P = 0.002, P = 0.032) were identified as independent prognostic factors for recurrence-free survival in patients with RCC. In our opinion, the result of this study proved the relationship between Eg5 expression and worse clinical outcome in RCC. This finding suggested that Eg5 served as a prognostic factor, which could be useful to predict cancer evolution and provide appropriate treatments for RCC patients.