Highly prevalent in the population older than 65 years, and leading to poor outcomes (functional decline and its related consequences), sarcopenia does not benefit yet either of a clear understanding of its patho-physiology. Its origin, its risk factors, its clinical presentation will be detailed. The diagnosis of sarcopenia imposes a clear identification of the risk factors, a specific muscular assessment, a pragmatic clinical approach. The treatment is based on nutritional supplements and/or drugs which to be active need to be associated to physical exercises of moderate intensity. Geriatricians are expecting new therapy to delay the consequences of sarcopenia, e.g. frailty and inability in daily living.