Wireless Sensor Networks has gained more importance in recent years due to its wide range of applications. Some of them are environmental and health monitoring, tracking of animals and monitoring, tracking and control of military, in ships for weapon sensor, mobile networks, radiation and nuclear-threat detection structure, communications and targeting systems. Sensors are low cost devices with limited storage and consume less power to provide solution to real-world problems. The structure of sensor networks is application -dependent. Efficient routing, network lifetime, power consumption forms the major issues in WSN and security forms the major issue in case of large network due to its power considerations. Clustering is the major factor which defines management of the network, distribution of address, topology update, quality of service and power consumption. Here, some of the clustering protocols are described Base Station Controlled Dynamic Clustering (BCDC), Data Routing for In-Network Aggregation (DRINA), Hybrid Energy Efficient Distributed Clustering(HEED), Optimized Energy Efficient Routing Protocol(OEERP) and the optimization of the clustering in Enhanced-Optimized Energy Efficient Routing Protocol (E-OEERP) based on particle swarm optimization (PSO). © International Science Press.