This chapter analyzes the performance of existing ad hoc routing protocols using simulations and a test bed. It also analyzes the use of a hybrid routing approach for ad hoc networks based on the results. The chapter briefly describes the ad hoc on-demand distance vector, dynamic source routing, and the temporally ordered routing algorithm as the most widely used reactive ad hoc routing protocols. It introduces the destination sequenced distance vector routing and the optimized link state routing as the most representative proactive ad hoc routing protocols. The chapter includes the results from a large set of simulations, and provides the measurements obtained from our test bed to seek confirmation of the accuracy of our propositions. It presents simulation results justifying the advantages and disadvantages of the reactive and proactive ad hoc routing protocols. The reactive routing protocols under analysis have clear drawbacks such as the excessive flooding traffic in the route discovery and the route acquisition delay.