We present the design and simulation of an adaptive MAC protocol based on the path-diversity routing information for ad hoc networks. As a routing protocol, a multipath routing protocol based on SPAFAR is used, where a route discovery algorithm finds multiple paths significantly reduce the delay in finding an alternate path. The information about multiple paths discovered in the network layer is exploited by the MAC layer in order to forward a frame over the best hop out of multiple hop choices. The performance of our approach is compared with IEEE 802.11 MAC through the simulation. The results show that our scheme exhibits a significantly better performance rather than the IEEE 802.11 MAC protocol in terms of packet overhead and end-to-end throughput.