Muscle satellite cells are responsible for the regenerative events in response to daily activity-related injuries or disease-induced muscle fibre insults. Because of their central role in the regenerative capacity of skeletal muscle, it is currently hypothesized that satellite cells might be involved in the age-related loss of muscle mass. Evidence supporting the role of intrinsic and extrinsic factors in the defective satellite cell function in aged skeletal muscle has been proposed. Arguments against this hypothesis have also been suggested. It is important to delineate the exact role played by satellite cells during aging in order to deliver adequate pharmacological or non-pharmacological treatment. Currently, there are important critical issues such as the species studied and the characterisation of the population included that need to be carefully considered in order to reach reliable conclusions and the question of whether the proliferation and differentiation capacity of human satellite cells is important in the dynamic regulation of myofibre size deserves further attention.