Security is an essential requirement in mobile ad hoc networks to provide protectedcommunication between mobile nodes. MANETs are vulnerable to various attacks; black hole is one of thepossible attacks. Black hole is a type of routing attack where a malicious node advertise itself as having theshortest path to all nodes in the environment by sending fake route reply.We attempt to focus on analysing and improving the security of one of the popular routing protocol forMANETS viz. the Ad hoc On Demand Distance Vector (AODV) routing protocol. Our focus specifically, ison ensuring the security against the Black hole Attacks. We propose modifications to the AODV protocol andjustify the solution with appropriate implementation.