: Numerous studies have shown the difficulty for a single routing protocol to scale with respect to mobility and network size in wireless ad hoc networks. This paper presents a cluster-based extension of the DSR protocol called Cluster Source Routing (CSR)1 . The proposed approach improves the scalability of DSR in high-density and low-mobility networks. The originality of our proposal is an adaptive use of DSR and CSR routing modes according to network density and node mobility in order to produce less overhead and perform efficient routing. Indeed, adaptation is a key feature for a routing protocol since network dynamics can suddenly and widely change in wireless ad hoc networks. Thus, the DSR-CSR protocol achieves enhanced performance over a broader {network density, node mobility} domain as shown by simulations. Key Words: wireless networks, ad hoc routing, clustering, adaptation, scalability. Category: H.3.7, H.5.4