In relay-assisted cellular networks, relay nodes are usually deployed in a cellular cell without taking the information about the place where it needs to be deployed. So sometime it will ultimately leads to wastage of resources. In this paper, we have focused on this problem and proposed a fuzzy-based methodology to find the optimum quantity and requirement of these relay nodes in cellular networks. Proposed methodology tackles with two problems, which are “where to deploy,” “how many relay nodes to deploy.” In cellular cell, users residing near the base station get higher data services and users residing near the boundary of cellular cell get lower data services. So this introduces unfairness for far users in terms of data rate. Relay-assisted networks are introduced to solve this problem. As the number of users is increasing day by day, so it is necessary to provide adaptive positioning of relay nodes for getting optimal services within limited infrastructure cost. In other words, relay-assisted cellular networks should be adaptive for traffic offered by specific area. In this paper, we have taken three parameters that strongly affect the position of relay nodes. These three parameters include user density in specific area, amount of high-speed data requirement from a certain area on regular basis and signal strength to tackle with dead zones over the entire cellular cell.