Age-related changes in physical function are attracting attention in Japan. Sarcopenia is known as the loss of skeletal muscle mass and strength in the elderly. Secondary sarcopenia due to neuromuscular disorders should be considered in patients with sarcopenia. Providing appropriate medical care for patients with neuromuscular disorders will extend healthy life expectancy. In this review, previous studies on age-related changes in the neuromuscular system were summarized and the common neuromuscular disorders in the oldest-old were reviewed.