Abstract: Objective To analyze the correlation between serum calcium level and tumor size/ stage in patients with renal cell carcinoma (RCC). Methods Totally 173 RCC cases were divided into 3 groups according to their serum calcium level, namely low, normal and high level groups. SPSS10.0 software was used for statistical analysis of the tumor sizes/stages and their association with serum calcium level in the 3 groups. Results and Conclusion Kruskal-Wallis H test revealed no significant difference in the tumor size between the 3 groups (χ²=4.768, df=2, P=0.092), but Spearman correlation analysis suggested inverse correlation between serum calcium and tumor size (r=-0.166, P=0.029). Kruskal-Wallis H test also failed to suggest significant difference in the tumor stage between the 3 groups (χ²=4.277, df=2, P=0.118), but serum calcium was found to beinversely correlated with the tumor stage (r=-0.157, P=0.039 by Spearman correlation analysis)