In recent decades, the main pathogenetic mechanisms for maintaining muscle mass and strength have been discovered. Most of the scientific papers on the molecular aspects of the pathogenesis of sarcopenia were focused on the Akt-signaling pathway. The subject of the study were people of elderly and senile age, immobilized patients, patients with CKD 1-4 stages, animals. However, recently more attention has been paid to the role of protein – the mammalian target of rapamycin mTOR. It seems to be a key link in the control of muscle mass and is a promising marker in understanding the mechanisms of the pathogenesis of sarcopenia. Its importance in protein metabolism in patients with end stage kidney disease is not studied and requires further research. The presented scientific review contains information on the role of mTOR and its components – mTORC1 and mTORC2 in maintaining muscle mass and strength in a healthy person and in the formation of sarcopenia in patients with CKD. The general aid of mTORC1 complex is regulation of protein production which is necessary for cell growth and differentiation. mTORC2 complex functions are not enough studied. It is established that it plays important role in such biological processes as cytoskeleton organization, intracellular homeostasis maintaining, so it provides cell resistance and cell survivability in negative external and internal impulses. mTOR protein can be considered as promising molecular marker in diagnostics of protein metabolism early disturbances in patients with CKD and also as additory factor of sarcopenia severity assessment.