Cross-layer design of routing protocol for mobile ad hoc networks (MANETs) has become a hot research topic in recent years. By integrating physical layer, MAC layer and network layer together for cross-layer design, a cross-layer routing protocol called MIR is proposed in this paper. Via predicting the duration of the interference imposed by the neighbors at every hop along the route, a new routing metric is presented which guarantees that the established routes will not break frequently while having the minimum interference. Simulation results show that MIR can significantly improve the network performance.