Mobile Ad hoc network is a set of mobile nodes with zero configurations and without any physical infrastructure and centralized computing. Several reactive routing protocols like Dynamic Source Routing, Ad Hoc On-Demand Distance Vector Routing, Destination-Sequenced Distance-Vector and several other protocols have been implemented. In this paper we have evaluated and compared the performance of two reactive routing protocols for mobile ad hoc networks: DSR and AODV. In the simulation DSR gives better performance than the AODV. In our performance evaluation we have used different parameters like network load, mobility, and network size. The simulations were carried out on ns-2.