Wireless sensor networks comprise of small nodes with sensing, computation and wireless communication capabilities. The energy efficiency is a substantial key design issues in such networks. An efficient routing protocol is critical to prolong the life of sensor nodes. Several methods for transmitting data in randomly deployed sensor nodes have been proposed, including direct communication, flat, and clustering protocols. This work presents a Hierarchy-Based Multipath Routing Protocol (HMRP) for wireless sensor networks. According to HMRP, the wireless sensor network is initially constructed as a layered network. Based on the layered network, sensor nodes have multipath routes to the sink node through candidate parent nodes. The simulation results indicate that the proposed HMRP can increase the lifetime of sensor networks better than other clustering or tree-based protocols. Key Words: Wireless Sensor Network, Energy Efficiency, Hierarchy-based Multipath Routing, Clustering Protocol,...