A MANET is a type of wireless network which does not require any predefined infrastructure to get established and is a collection of mobile nodes forming a network by their own. The performance of MANETS depends upon various factors such as routing technique, size of network, density of network, power and bandwidth etc. Mobility model is a representation of reality of a scenario in which nodes may move in real environment. It provides an insight that how each node may move under given circumstances. The paper is to study the impact of mobility models on the performance of routing protocols in mobile ad hoc networks.