A Wireless Sensor Network (WSN) contains a large number of sensor nodes equipped with limited energy supplies. In most applications, sensor nodes are deployed in a random fashion. Therefore, battery replacement or charging is considered not practical. As a result, routing protocols must be energy-efficient to prolong the network’s lifetime. In this paper, the authors propose a new Dynamic Re-clustering LEACH-based protocol (DR-LEACH) which aims to reduce the energy consumption and extending the network’s lifetime. The idea is to balance energy consumption of Cluster Heads (CHs) by generating clusters with almost equal number of nodes during each round of the network life time. To perform this, they first calculate the optimal number of CHs in each round and based on that they calculate the optimal size of each cluster.