A wireless sensor network (WSN) is composed of a large number of sensor nodes which are resource constraints, e.g., limited power. This drives research on how to design routing protocols to gather data efficiently so that the life of the network can be prolonged. A usual concept to collect data by a sink node is to transfer data from sensor nodes to the sink node by multi-hop. However, it gives rise to two problems. The first one is the hotspot problem, in which the sensor nodes closer to the sink run out of energy sooner than other nodes. As a result, the network loses its service ability, regardless of a large amount of residual energy of the other nodes. The second one is that the network generates unnecessary traffic during data transmission for choosing a proper data sending path. To resolves the problems, we, in this paper, propose a new energy balanced and efficient data aggregation scheme for WSNs, called designated path (DP) scheme. In DP scheme, a set of paths is pre-determined and run them in round-robin fashion so that all the nodes can participate in the workload of gathering data and transferring the data to the sink. Through analytical performance evaluations and simulation results, we show that our DP scheme is more energy efficient and it can prolong the life time of the network than the existing schemes directed diffusion (DD) and hierarchical data aggregation (HDA).