Wireless Sensor Networks (WSNs) is a collection of sensing devices that can communicate wirelessly where each device can sense, gather and deliver or process the data to its peers. WSNs is an “exciting emerging domain of deeply networked systems of low-power wireless motes with a tiny amount of CPU and memory, and large federated networks for high-resolution sensing of the environment”. As generally sensor nodes work with battery powered devices, so the main emphasis is how to reduce the energy consumption of nodes, so that the lifetime of network can be increased. There are several energy efficient hierarchical routing protocols. Amongst these, the authors have simulated LEACH in NS2 with MANNASIM framework and analyzed the performance of LEACH(Low Energy Adaptive Clustering Hierarchy) in terms of alive nodes, frames, bits from cluster.