Wireless networks are expanding day by day, as everyone wants wireless connections. If we talk about Mobile Ad-hoc Network (MANETs), this is one of the vulnerable wireless networks due to lack of central co-coordinator. Any malicious nodes can threat the security of MANETs very efficiently. Black-Hole attack is one of the security threat in which the malicious node attract packets from source node by broadcasting the shortest route to destination and drop packets without delivering to the destination node. The main aim of this paper is to study the effect of Black-Hole attack in MANET using Ad-Hoc on Demand Distance Vector (AODV) which is a Reactive routing protocol. The simulation of MANETs with 15, 25, and 50 nodes is done and comparison of performance parameters such as PDR and throughput of Black-hole affected MANET and the normal network is taken into account for low, medium and high traffic intensities. Simulation is done in NS-2. © 2017 IEEE.