Abstract: In cognitive radio relay networks, the resource allocation technique may result in increased power consumption and interference. In this study, we propose to design a fuzzy based resource allocation technique for cognitive radio relay networks. In this technique, a Proportional Fair Scheduling (PFS) based resource allocation is applied for all nodes in which node with good channel condition and high data rate is allocated more bandwidth. Then the adaptive transmit power adjustment algorithm used for optimal resource allocation. A Fuzzy Logic Decision (FLD) model is used for selecting the transmit power level based on the factors interference among relay nodes, transmission rate between relay and mobile node and predicted link availability. By simulation results, we show that the proposed technique reduces the energy consumption and link interference.