We examined 342 healthy men aged 20 to 89 years to establish age-related changes in body composition in physiological aging. Body composition was assessed by dual-energy X-ray absorptiometry (fat and lean mass of the body, trunk and extremities, fat content, fat mass index, lean mass index, appendicular lean mass and appendicular lean mass index). The study found an age-associated decrease in lean mass and an increase in fat mass. The related index of fat mass significantly increased in aged men, reaching the maximum in the age group 50–59 years – 8.44 [6.19 – 10.33] compared with the group of 20-29 years old men – 5.24 [4.00 – 7.01] kg/m2 (P < 0.001). The appendicular lean mass reached a maximum in men 30-39 years old and decreased with age. The loss of lean mass at the age of 40-49 years was 5.2%, 50-59 years – 8.1%, 60-69 years – 9.3%, 70-79 years – 18.5%, 80-89 years – 22.1%. The incidence of sarcopenia probably increased with age and was in the age groups of 50-59 years – 5.3%, 60-69 years – 5.1%, 70-79 years – 15.1%, 80-89 years – 41.0%. Conclusively, age-related features of the body composition in men consisted of a decrease in lean mass with an increase in the frequency of sarcopenia from 5.3% in the age group 50-59 years to 41.0% in the age group 80-89 years on the background of increasing body fat.