The senescence program is activated in response to diverse stress stimuli potentially compromising genetic stability and leads to an irreversible cell cycle arrest. The mTOR pathway plays a crucial role in the regulation of cell metabolism and cellular growth. The goal of this chapter is to present evidence linking these two processes, which have one common regulator-the tumor suppressor p53. While the role of mTOR in senescence is still controversial, recent papers have shed new light onto this issue. This review, far from being exhaustive given the complexity of the field, will hopefully stimulate further research in this domain, whose relevance for ageing is becoming increasingly documented.