The purpose of this study was to investigate the effect of aging on the DNA methylation status of two genes involved in tumorigenesis (telomerase gene hTERT and DNA repair gene-MLH1) and one in metabolism (methylenetetrahydrofolate reductase gene-MTHFR) in oral epithelial cells. DNA methylation analysis was performed by Methylation Sensitive Restriction Enzymes (MSRE) of healthy oral epithelial cells of child (6-10 years, n=21), young (20-25 years, n=19) and elderly (over 60 years, n=25