Sarcopenia is defined as generalized and progressive age-related loss of skeletal muscle mass, muscle strength and physical performance below a defined threshold. In sarcopenia skeletal muscle mass - the largest body organ - is failing in its function and the term "muscle failure" was suggested. Sarcopeniat is now recognized as a serious clinical problem compromising healthy aging concept and quality of life of affected older people. Sarcopenia has a complex multifactorial pathogenesis, which involves not only age-related changes in neuromuscular function, muscle protein turnover, and hormone levels and sensitivity, but also a chronic pro-inflammatory state, oxidative stress, and behavioral factors - particularly nutritional status and degree of physical activity. The paper provides detailed review of screening and diagnostic methods and consensus-based cut off values and biomarkers of potential patophysiologic mechanisms involved in sarcopenia development in individual patient. Further, detailed description of current preventive and therapeutic strategies for sarcopenia is included. These involve structured physical activities, namely progressive resistance training and aerobic activities which prevent muscle loss and improve muscle performance. The effect of exercise is enhanced by nutritional supplementation, particularly through proteoanabolic effect of proteins and some amino acids. There are no currently registered drugs with indication of sarcopenia but there are promising substances in higher phases of clinical trials (such as antimyostatin human monoclonal antibodies, selective androgen receptor modulators) which have the potential to be introduced into clinical practice soon. Conclusions Sarcopenia is a new clinical diagnosis of organ failure of the skeletal muscle function leading to multiple adverse health outcomes. Physicians should be aware of clinical symptoms and diagnostic algorithm and target treatment according to sarcopenia leading causes. Key words: clinical diagnosis and treatment - muscle failure - muscle mass, strength and function - sarcopenia.