Energy (battery) of the sensor node is considered as the scarcest resource in Wireless Sensor Network (WSN), hence a communication protocol that efficiently uses the limited energy must be developed. In this paper, Region-based Energy-aware Clustering (REC) scheme is presented to optimize the energy usage, with clustering has been identified as an effective data forwarding technique in WSN. With REC, algorithms for energy efficient cluster formation, cluster head selection, and inter-cluster communication is proposed. Using OMNet-4.0 simulation tool, the performance of REC is compared with LEACH and EEMC, using performance metrics of energy per packet and average delay. Simulation results demonstrated that the proposed protocol of REC is effective in prolonging the network lifetime, as well as supporting for scalable network. © 2010 IEEE.