An IIDS mechanism has been proposed for identification of such attacks and alerting the normal sensor nodes for reduction of data loss rate. The simulation result shows that the vulnerability like sinkhole attacks on WSN drops all the transmitted packets across the leader. The proposed IIDS captures the sinkhole nodes with the minimum computation and alerts the normal sensor nodes. Since the computation of proposed Intelligent Intrusion Detection System (IIDS) is simple, it consumes less energy, whereas the network lifetime can be extended as compared to the existing work, namely, Low-Energy Adaptive Clustering Hierarchy (LEACH) and MS-LEACH.