In this thesis we investigate the efficiency of routing protocols for Mobile Ad Hoc networks (MANETs) by adopting an experimental approach. MANET routing protocols have been mainly evaluated through simulations which often introduce simplifying assumptions (e.g., radio propagation model) and mask important real characteristics. To avoid these modeling approximations, it is necessary to complement simulation with experiments on real MANETs. This work provides a contribution in this direction reporting our experiences learned by these real measurements. By setting up MANET prototypes, firstly we investigate IEEE 802.11 behavior in single­hop MANETs, secondly we focus on an innovative analysis of routing protocols in multi­hop MANETs by varying scenarios. To the best of our knowledge, our medium­scale scenario composed of 23 nodes represents one of the largest MANET testbed. Our experimental results highlight that, in contrast with MANET community, by using proactive routing protocols the overall system gains in scalability, performance and efficiency. These results encourage us identifying in this last class Hazy Sighted Link State (HSLS) as a more suitable protocol. A further contribution of this thesis is hence to design, develop and test an enhanced version of HSLS, strengthened with a mechanism to guarantee the reliability of LSU packets without additional control overhead, and a module to support middleware-network interactions as proposed by the MobileMAN project (EUIST-FP5-FET-Open-IST-2001-38113).