Abstract. This talk is driven by a general motto: bisimulate a hybrid system by a finite symbolic dynamical system. In the case of o-minimal hybrid systems, the continuous and discrete components can be decoupled, and hence, the problem reduces in building a finite symbolic dynamical system for the continuous dynamics of each location. We show that this can be done for a quite general class of hybrid systems defined on o-minimal structures. In particular, we recover the main result of a paper by Lafferriere G., Pappas G.J. and Sastry S. on o-minimal hybrid systems.We also study related decidability questions. This is joint work with Thomas Brihaye, Cˇdric Rivi¸re and Christophe Troestler.