Background. At this stage of the development of wireless technologies, there is a rapid growth in the volume of information services, as well as the speed of information transfer. To meet these needs, additional frequency bands should be used. However, at the moment most of the radio spectrum is already occupied for use. To solve this problem, the concept of cognitive radio can be used, the effectiveness of which mostly depends on the algorithms for detecting signals in frequency channels. Objective. The aim of the work is to investigate algorithms for detecting unknown signals during radio monitoring in cognitive radio networks. Methods. Investigation of algorithms for detecting unknown signals was carried out by the method of statistical tests. Results. The quality of detection of unknown signals is investigated. The proposed detection algorithms should increase the detection efficiency of unoccupied frequency channels, and thereby improve the functioning of cognitive radio networks. Conclusions. The work deals with nonclassical methods of detecting unknown signals, the application of which is possible within the framework of the concept of cognitive radio. These methods differ from the classical ones in that they use information only about noise. As a result of computer research, estimates of the detection quality of unknown signals were obtained. These estimates confirm the operability and the possibility of using the proposed algorithms in radio monitoring in cognitive radio networks. Keywords: cognitive radio; methods of signal detection; unknown radio signals; radio monitoring; radio spectrum; frequency resource; unknown signals.