Efficient routing protocols design is a critical approach for energy conservations in wireless sensor networks. In this paper, we propose an energy efficient routing protocol, named as cluster-based directed hierarchical routing protocol (CB-DHRP). The design philosophy of CB-DHRP is conceptually similar to the well-known LEACH scheme, but different in the assumptions of node transmission range and the formation method used in routing structure creation. Bound on the limited node transmission range, and with the cooperation of cluster members and cluster heads, CB-DHRP always constructs energy-efficient transmission paths that are capable of relaying the sensed data toward the sink (Base Station, BS). The simulation results show that, by choosing an appropriate percentage of cluster heads, the proposed CB-DHRP protocol can achieve about 1.5 times improvements on the network lifetime than that in other existing protocols, such as LEACH, ERA, and PEGASIS protocols.