Wireless Sensor Network (WSNs) are commonly deployed in hostile (unattended) and open environments, where it is easy for an attacker to physically capture some of the legitimate nodes, copy credentials, reprogram them and re-deploy them in the WSN. Such type of attack is called Node Replication or Clone Node Attack. With this attack an attacker can easily gain significant control over the WSN. In the literature, several schemes have been proposed to detect Clone Node Attack in general; however, limited work has been done for the prevention of this attack in mobile WSNs. Consequently, in this paper we present an approach to prevent Clone Node Attack in mobile WSNs. Since the proposed scheme neither uses node's physical location information nor any other complex computational intensive algorithm, it is best suited for memory and computationally constrained sensor nodes. In order to evaluate the proposed scheme, we have exploited five different scenarios in which adversary can launch replicas/clones in the WSNs. These scenarios are examined theoretically as well as practically.