Background: To discover new epigenetic biomarkers for early cancer detection. The CDH11 gene has been reported as a critical tumor suppressor gene (TSG) for multiple tumors, although it has not yet been reported in renal cell carcinoma (RCC). We explored its epigenetic alteration in RCC and analyzed the possible biological function and mechanism in tumorigenesis and progression of RCC.Materials and Methods: We examined CDH11 gene expression and methylation using semiquantitative reverse transcriptase PCR (RT-PCR) and methylation-specific polymerase chain reaction (MSP) in RCC cell lines before and after treatment with 5-aza-2’-deoxycytidine (5-Aza). MSP was further applied to 93 RCC primary tumors, and the relationship between CDH11 gene methylation and clinicopathological features was discussed. A selection of the cell lines and specimens was subsequently examined using bisulfite genomic sequencing (BGS) and real-time PCR. Meanwhile, assays of cell viability, colony formation, migration and invasion, wound healing, and western blot were performed to confirm the tumor-suppressive function and mechanism of CDH11 gene.Results: CDH11 gene methylation was detected in 4 of 5 RCC cell lines with silenced expressions. Treatment with 5-Aza reversed methylation and restored CDH11 gene expression. Aberrant methylation was further detected in 41 of the 93 (44.1%) primary tumors. Furthermore, CDH11 gene methylation was significantly associated with tumor stage and nuclear grade in patients with RCC (p<0.05). Due to the phenomenon of aberrant methylation, ectopic low-level expression of CDH11 gene could result in promotion of tumorigenesis and progression in RCC cell lines, which might be mediated through NF-kB pathway. Conclusions: The CDH11 gene is often down-regulated by aberrant promoter methylation in RCC cell lines and primary tumors, indicating its critical role as a TSG in RCC. It may be involved in the tumorigenesis and progression in RCC through NF-kB pathway, thus which could potentially serve as a novel biomarker and therapeutic target for RCC.