In this paper, we propose a power efficient MAC protocol (PEMP) for IEEE 802.11 multihop ad hoc networks. Most of related work targeted at single hop ad hoc networks. In PEMP, when a node intends to transmit data, it will piggyback a data profile, which includes data size, on ATIM* and ATIM-ACK*. ATIM* and ATIM-ACK* are ATIM and ATIM-ACK with piggybacked data profiles, respectively. In this way, senders and receivers can inform their neighbor nodes of their data profiles. Then, each node calculates its transmission priority according to the collected data profiles. Based on transmission priorities, PEMP can schedule a better transmission sequence to reduce power consumption. By decreasing the idle time in the active state and adjusting the ATIM window dynamically based on network conditions, the power consumption of PEMP is 20% and 10% ∼ 30% less than that of DPSM and IEEE 802.11 PSM, respectively. PEMP is applicable to multihop ad hoc networks and can achieve a good tradeoff between power consumption, throughput and delay.