Sarcopenia refers to age-related muscle loss, defined using a combination of appendicular muscle mass, muscle strength, and physical performance measures. The pathogenesis depends on a balance between positive and negative regulators of muscle growth. Sarcopenia increases the risk for falls, fractures, dependency, use of hospital services, institutionalization, poor quality of life, and mortality. In clinical practice, brief screening tools, such as the 5-item SARC-F score, may be useful. Although pharmacologic treatments are actively being studied, the current mainstay consists of optimizing nutrition status, in particular protein and vitamin D status, and resistance exercises.