From the last decade, the use of internet and its growth is continuously increasing. Similarly, numbers of services are coming out along with the internet and it is being used for providing facilities to human beings. Accordingly, attacks on these services are also increasing. It is require to build defense and network monitoring system for identifying attacks and prevent them. Intrusion detection system (IDS) plays an important roles to detect threads inside the system and generate the alert related to the attack. Wireless sensor network(WSN) is formed using small mobile nodes; these mobile nodes are able to perform computation, sensing the various types of signals and then perform communication with other nodes. Wireless sensor nodes has various issues because of that, it experiences number problem related to its functionalities and some malfunction due to attacks. In this paper, we are focusing on intrusion detection system in wireless sensor network. © 2019, Institute of Advanced Scientific Research, Inc. All rights reserved.