Transhumanism is a philosophical movement that has been in development for 50 years. This movement supports the goal of an augmented humanity that is freed from biological limitations using artificial intelligence, converging NBIC (nanotechnology, biotechnology, information technology and cognitive science) technologies and enhancement. The aim is to combat aging in order to ultimately achieve immortality. Transhumanism aims to transform the human being, in view of the posthumanism that will emerge when the radical transformation of human nature is achieved, with the creation of a superintelligence according to an evolutionist plan. The existential risks generated by some applications of NBIC technologies and artificial intelligence (AI) have been discussed for a decade. An ethical and scientific debate has emerged that opposes transhumanists, who describe themselves as bio-progressives (AI specialists) in comparison to bio-conservatives (biologists). This article shall not put forward the scientific arguments of biologists who believe that human immortality is impossible, but it shall rather present the social, economic and philosophical context of the transhumanist movement, founded on a belief of possible immortality. Can Humans be freed from their biological limitations? The context of transhumanism Social and scientific legitimacy of transhumanism The contribution of Artificial Intelligence The actors in transhumanism Who are the transhumanists? The figth against aging Ethical limits to the developpement of NBIC technologies The debate References Further reading and relevant websites