Abstract: A multicast protocol utilizing on-demand routing strategy for mobile packet radio network is proposed. The protocol is a mesh-based multicast scheme. It does not maintain permanent route tables with full topological views. Instead, it applies on-demand procedures to discover routes dynamically and build multicast forwarding groups. The multicast packets are propagated by each forwarding group member via scoped flooding, so the protocol can reduce network bandwidth overhead and avoid the propagation of potentially large routing updates throughout the network. Simulation results show that the multicast protocol is robust to mobility, has low bandwidth overhead, scales well with membership group size, and can be used effectively for mobile packet radio networking.