Introduction: The daily lifestyles of Thai Buddhist monks and Thai males differ due to Buddhist practices, which potentially affect telomere length. Telomeres are DNA compounds located at the ends of chromosomes that shorten with each cell division. This study investigated the difference in telomere length between Thai Buddhist monks and Thai males aged ≥40 years. Method: This was a cross-sectional study involving 100 Thai Buddhist monks aged ≥40 years who had been ordained for more than five years and 100 Thai males aged ≥40 years. General information and health information were assessed by questionnaire. Nutritional status was determined by body composition and blood chemistry parameters. Telomere length was measured by Monochrome Multiplex RealTime Quantitative PCR and expressed as T/S ratio. Result: Mean telomere length of Thai Buddhist monks was longer than that of Thai males (1.08±0.18 vs. 1.02±0.17; p<0.050). In both groups, the mean telomere length in subjects aged ≥60 years was shorter than that in subjects aged 40-59 years (p<0.010). Alcohol consumption, which affected Thai males (p<0.050), but meditation tend to slow down the shortening of telomeres (r=0.167; p<0.050) in both groups. Conclusion: Age was the parameter that affected telomere length the most. Furthermore, various factors in the Buddhist monk group, such as a peaceful lifestyle, meditation, non-alcohol consumption, and fewer underlying diseases, could explain for the longer telomere lengths in this group.