Background and Objective: Security is one of the major issues in wireless sensor networks, due to its wireless and resource constrained nature. Techniques like authentication, authorization and cryptography fail to assure secure communication, once a sensor node in the network is compromised. In such cases, Trust model plays a crucial role in securing the sensor networks, by identifying the selfish, malicious and compromised nodes and isolating them from communication. It also helps in efficient key distribution, resource utilization, and cluster formation, routing and data aggregation in sensor networks. Materials and Methods: This paper presents different trust metrics and models proposed recently, to address various attacks identified by monitoring their behaviour in the network. Conclusion: It also presents how the trust model is used in different stages of communication to make decisions regarding selection, participation and importance of nodes in the network. © 2016, International Journal of Pharmacy and Technology. All rights reserved.