The purpose of this study was to compare serum lipid and blood glucose levels in young and middle-aged Zen monks, and to clarify the influence on physiological change in body by aging. The eighteen Zen monks who lived in a Zen temple (a young group of twelve average aged 24.3, and a middle-aged group of six average aged 59.2) were investigated their body measurement, life activity survey, dietary survey, evaluation of health-related quality of life, and blood test.   As a result, a significant difference between the two groups was not recognized in BMI, body fat percentage, energy consumption, nutrient intakes, and evaluation of health-related quality of life. Identically, in both of the groups, a distinct difference was not observed in HDL cholesterol and triglyceride levels. However, total cholesterol and blood glucose levels of the young group were remarkably higher than those of the middle-aged group.   Therefore, this study suggested that physiological change in body by aging affected the total cholesterol and blood glucose levels.