Abstract: Objective: To detect promoter methylation and mRNA expression of phosphatase and tensin homologue (PTEN) in gastric carcinoma and to analyze their relationship with the clinical and pathological features. Methods: Methylation- specific PCR and RT- PCR were employed to detect promoter methylation and mRNA expression of the PTEN gene in gastric cancer tissues and their adjacent tissues from 56 patients. Results: Promoter methylation was found in 48.2% (27/56) of the carcinoma tissues and 3.6% (2/56) of carcinoma- adjacent tissues, and the difference was significant (P<0.05). In the 29 cases with lymph node metastasis, 19 cases were observed with PTEN promoter methylation. PTEN mRNA was not expressed in tissues with methylation of the PTEN promoter. Conclusion: Loss of PTEN transcription is associated with methylation of its promoter in gastric carcinoma and it may play an important role in the carcinogenesis and metastasis of gastric carcinoma.