Abstract: Wireless sensor networks often face the critical problem of maintaining the sufficient sensing coverage (QoS) at an application specific level while keeping a small number of nodes active at any time to save energy. To solve this problem, the relationship between the desired QoS requirement and the minimum number of active nodes is analyzed without the knowledge of location or directional information in the randomly deployed sensor networks. Based on the analytical results, an energy efficient and location-independent QoS (ELIQoS) protocol is proposed, which selects the minimum number of active nodes based on the nodes' energy without using any location information. Simulation and analysis study demonstrates that the ELIQoS protocol can not only reduce the network consumption and balance the energy dissipation among nodes, but can provide the desired QoS requirement effectively.