Sarcopenia is an evolving concept and the current definition of sarcopenia includes both a loss of muscle strength and loss of muscle mass. However, despite the increasing knowledge and improved technology, a worldwide operational definition of sarcopenia applicable across racial/ethnic groups and populations lacks consensus. As a result the prevalence of sarcopenia (8 to 40% of older people over 60 years) varies depending on the study sample (namely the age of the sample), the definition, and the assessment tool used. DXA is the main assessment method used to evaluate muscle mass, which is further adjusted to height, weight fat mass, or BMI to obtain an index of sarcopenia. Cross-sectional analyses seemed to prove an association between low muscle mass and functional decline, but these results were not consistent when analysed longitudinally over time. This inconsistency could be due to methodological issues as the selected populations in the cohorts where autonomous, community-dwelling, older people. In this highly active population decreases in muscle mass might be not as important as decreases in strength to predict functional decline. The aim of the present paper was to perform a comprehensive review of the literature on the epidemiology of sarcopenia and its consequences to be presented on November 13th and 14th 2008, at the Carla Workshop.