Abstract: Cognitive radio is an opportunistic communication technology designed to help unlicensed users utilize the maximum available licensed bandwidth. Selfish cognitive radio attacks are a serious security problem because they significantly degrade the performance of a cognitive radio network. The proposed work provides selfish cognitive radio attack detection technique, called COOPON, which will detect the attacks of selfish Secondary Users by the cooperation of other legitimate neighboring SUs. The COOPON algorithm make use of the autonomous decision capability of an ad-hoc communication network based on exchanged channel allocation information among neighboring SUs.