This paper proposes energy efficient LEACH protocol for secure data transmission for wireless networks. The proposed work uses Networks Simulator – NS2.27 for the simulation of cluster based routing protocol LEACH in wireless sensor network. The work is to enhance the performance of LEACH in terms of energy saving and secure data transmission. Instead of random selection of Cluster Head (CH) the selection method is based on residual energy and vicinity of the node. With this hybrid approach, the node, which is eligible for the CH, will become cluster head and it enhances the performance of traditional LEACH. Traditional LAECH does not support secure data transmission and authentication of nodes in the clusters. By adding security between CH and CM using XOR function and key management, secure data transmission and authentication is carried out for selected application where security is the most important aspect. The proposed LEACH enhances lifetime of the wireless sensor network with security.