A mobile ad-hoc network (MANET) is a collection of mobile nodes which communicate over radio. These networks have an important advantage, they do not require any existing infrastructure or central administration. Therefore, mobile ad-hoc networks are suitable for temporary communication links. This exibility, however, comes at a price: communication is dif cult to organize due to frequent topology changes. In this paper we present a new on-demand routing algorithm for mobile, multi-hop ad-hoc networks. The algorithm is based on ant algorithms which are a class of swarm intelligence. Ant algorithms try to map the solution capability of ant colonies to mathematical and engineering problems. The Ant-Colony-Based Routing Algorithm (ARA) is highly adaptive, ef cient and scalable. The main goal in the design of the algorithm was to reduce the overhead for routing. Furthermore, we compare the performance of ARA with other routing protocols, including DSDV, AODV, and DSR through simulation results.