Abstract: To set up and maintain paths in mobile ad hoc networks,an adaptive routing protocol based on ant colony algorithm for ad hoc networks is proposed.The routing protocol uses ant agents to find a path to a destination node at the start of each data session,and during the course of the session,uses ant agents to test existing paths and repeatedly explore new ones.It dynamically sets up and maintains multiple paths between the source and the destination of a data session,and makes the protocol adapt for the dynamic topology networks.Simulation results show that the adaptive routing protocol can outperform AODV and W_AntNet in terms of average packet end-to-end delay and packet delivery ratio.