The scalability and stability in wireless sensor networks (WSNs) are considering as an important issue due to the large numbers of nodes and consequently their node density and deployment. While the network size increase, the need of scalable and efficient routing protocols is indispensable. Moreover, sensor nodes have to be alive to guarantee the network operation for the period which the first node died doesn’t appear. This period, named network stability region, is ameliorated by many techniques. In fact, the balancing energy consumption and clustering method are among those techniques. In this paper, we present the scalability and stability analysis of the routing protocol LEACH based on K-means clustering algorithm (KLEACH). Accordingly, the simulation results of the performance metrics verify the efficiency and the scalability of KLEACH protocol compared to LEACH.