This paper is devoted to Poincaré's work in probability. Though the subject does not represent a large part of the mathematician's achievements, it provides significant insight into the evolution of Poincaré's thought on several important matters such as the changes in physics implied by statistical mechan- ics and molecular theories. After having drawn the general historical context of this evolution, I focus on several important steps in Poincaré's texts dealing with probability theory, and eventually consider how his legacy was developed by the next generation.
