Objective: To discuss the relation between the methylation of Dactl promoter and expression of Dactl mRNA in renal cancer. Methods: The tissue specimens from 30 cases of renal cancer and corresponding nomal tissues were included,and CpG island methylation of Dact1 gene was detected by methylation specific PCR(MSP),and the mRNA expression of Dactl was evaluated by reverse transcription-polymerse chain reaction(RT-PCR). Results: The expression of Dactl mRNA was silenced in 19(63%) and down-regulated in 7(23%) specimens of renal cancer tissues,while down-regulated in 2 (6%) specimens of adjacent control tissues. The positive rates of methylation of Dactl promoter in renal cancer tissues and the corresponding control tissues were 70% and 6%,respectively. The positive rate in renal cancer tissues was significantly higher than that in the corresponding control tissues(P < 0.01). The correlation analysis of the silencing and down-regulation of Dactl gene and the methylated condition of Dactl promoter displayed statistical significance(P < O.05). Conclusion: The silencing or down-regulation of Dactl mRNA maybe participate in the renal carcinogenesis,and is related to the methylation of Dactl promoter.