Sarcopenia is the loss of skeletal muscle mass that occurs with ageing, and is a major contributing factor to disability and loss of independence in the elderly. The etiopathogenesis involves a number of underlying mechanisms including intrinsic changes in the muscle and central nervous system, and hormonal and lifestyle factors. Many hormones and cytokines affect muscle mass and function. Reductions in testosterone and estrogens that accompany ageing appear to accelerate loss of muscle mass. Growth hormone has been hypothesised to contribute to loss of lean body mass. Although sarcopenia is not completely reversed with exercise, physical inactivity leads to accelerated muscle loss. The diagnosis of sarcopenia is difficult because the most reliable methods to measure muscle mass are not easily available. Various treatment strategies have been tested for combating the loss of muscle mass: testosterone replacement and other anabolic androgens for men, estrogen replacement in women, growth hormone replacement, nutritional treatment and physical training. Only high resistance exercise training has been effective in increasing muscle mass, with or without nutritional supplementation.