Recently, it was examined the methylation status of the Protein Gene Product 9.5 (PGP9.5) gene in primary tumors derived from 49 patients with colorectal cancer and evaluated the correlation between the methylation status and the clinicopathological findings. A significant difference was observed in lymph node metastasis (p = 0.029), suggesting that PGP9.5 was less frequently methylated in metastatic colorectal cancer. This result prompted us to examine the methylation status of the PGP9.5 gene in gastric cancers.It was examined the methylation status of the PGP9.5 gene in primary tumors derived from 30 patients with gastric cancer using qMSP and evaluated the correlation between the methylation status and the clinicopathological findings.Aberrant methylation of the PGP9.5 gene was detected in 5 of 30 (17%) primary gastric cancers. The present results suggested that the aberrant methylation of the PGP9.5 gene was frequently observed in gastric cancers. Subsequently, clinicopathological data were correlated with the methylation results. A significant difference was observed in extent of tumor, lymph node metastasis, and TNM stage (p = 0.034, 0.015, and 0.028, respectively).PGP9.5 was less frequently methylated in advanced gastric cancer compared to earlier one.