The state in which physical and mental functions are deteriorated with aging is called frailty, and decrease in muscle mass and muscle strength with aging accompanying deterioration of physical function is called sarcopenia. Frailty and sarcopenia are found in older adults, which is a major obstacle to achieve healthy longevity. Estimation of prevalence and number of patients, as well as elucidation of risk factors in frailty and sarcopenia are important for the prevention of frailty and sarcopenia. The prevalence of frailty determined by criteria based on the method of Fried et al. was 5.2% for men and 20.9% for women in a cohort of randomly selected community-living population, and the estimated number of people with frailty was about 0.77 million men and 2,22 million women among the population aged 65 years and over in Japan. The prevalence of sarcopenia by the Asian Working Group for Sarcopenia (AWGS) criteria was 9.6% for men and 7.7% for women. The number of people aged 65 years and over with sarcopenia in Japan was estimated to be 1.64 million for men and 1.39 million for women. The onset of frailty was related to physique, physical function, cognitive function, depression, and various chronic diseases. Depression and lack of exercise were significant risk factors of sarcopenia. Physical activity, nutrition and control of chronic diseases are required for the prevention of frailty and sarcopenia, and the prevention will be an important issue for health and longevity in Japan.