The idea of the infinite is, for Descartes, very paradoxical: It is both the most clear and distinct, as well as the most incomprehensible idea that one can have. The paradox even reaches its positivity, for the in-finite is negatively formulated. Numerous authors were concerned by this issue during Descartes’ time, and even today, some still see it as a deep contradiction in his thought. This paper first exposes the paradox of the cartesian infinite, then shows how Descartes had already resolved it and how it will be understood by its posterity.