Nowadays, it is well known that with advancing age individuals are at an increased susceptibility to develop diseases such as Alzheimer's disease, infectious diseases, cancer, and osteoporosis. Ageing is associated with various changes in immune parameters: therefore many authors have postulated that these age-related diseases could be explained, at least in part, by an overall deregulation of the function of the immune system. Immunosenescence is the term usually used to describe the acquired dysfunctional immunity within the ageing population affecting both innate and adaptive immunity. The present review examines the close involvement of the immunosenescence in the pathogenesis of these main age-related clinical outcomes, insulin resistance and the frailty process.