Ad-hoc networking allows users to form temporary wireless networks without existing infrastructure. Each node acts both as host and router and must therefore be willing to forward packets for other nodes. This is done using a Mobile Ad-hoc NETwork (MANET) routing protocol. Frequent topology changes make such routing challenging. Existing protocols include Dynamic Source Routing (DSR) [3], the Cluster-Based Routing Protocol (CBRP) [5], and the Ad hoc On-demand Distance Vector (AODV) [11] protocol, among others. Using existing protocols, however, some nodes may be unduly loaded and end-to-end delay may be high. Further, existing protocols are hard to upgrade once they are in use. To address these problems, a new routing protocol, MARP, using mobile agents is presented. Mobile agents are software entities that can move between network nodes and execute programs they carry with them wherever they are running. Our agent-based algorithm implements a demand-based protocol that provides efficient routing at the application layer. A proof of concept implementation has been developed using Aglets [6] and simulated to evaluate its performance. The details of the protocol and its performance are reported in this paper.