An Ad Hoc network is a temporary network without infrastructure, dynamically formed by mobile devices without turning to any existing centralized administration. To send packets to remote nodes, a node use other nodes as intermediate relays, and ask them to transmit its packets. For this purpose, a routing protocol is needed. Because mobile devices are used, the network topology is unpredictable and can change at any time. The objective of this paper is to know the effect of mobility on the performance of Ad Hoc routing protocols, based on multi simulations performed with Glomosim.