In sarcopenia, muscle volume and strength decrease with ageing, disturbing activity of daily life in the elderly. We investigated risk factors of sarcopenia including life-style, nutrition intake and past history in randomly selected community living population aged 40 years and over. The subjects were 1,783 men and 1,825 women. They were followed up 10 years and repeatedly measured, we made a total of 14,010 measurements. Smoking, lack of exercise, shortage of energy, protein, branched-chain amino acid intake, and low self-rated health were risk factors of sarcopenia determined by muscle volume in dual-energy x-ray absorptiometry (DXA). Risk factors of sarcopenia determined by physical performance were also investigated in subjects aged 65 years or over. Smoking increased risk of sarcopenia, and intakes of total energy, vitamin D, protein and branched-chain amino acid significantly decreased risk of sarcopenia. However, physical activity was not related to incidence of sarcopenia.