Introduction. Passive radars perform target detection based on reflected signals emitted by third-party transmitters. The absence of its own transmitter determines the main advantages of passive radars compared to conventional active radars: lower cost, silent operation, no electromagnetic impact on other radio equipment and the environment. Third-party transmitters of different telecommunication systems are currently used as illuminators of opportunity in passive radars. The emergence of new telecommunication standards opens additional prospects for the development of passive radars. For instance, the deployment of the fifth generation of mobile communications standard 5G with a higher bandwidth can potentially improve the accuracy of target detection in passive radars. Investigating the possibility of using signals from 5G transmitters for radar targets illumination is a relevant research task.Aim. To analyze the possibilities, limitations and prospects of using 5G signals as illuminators of opportunity in passive radar systems.Materials and methods. The methods of passive radar theory, communication theory, and comparative analysis were used. Evaluation of potential characteristics of target detection was carried out using computer statistical modelling in the MATLAB environment.Results. The peculiarities of 5G signals from the point of view of their application as illumination signals in passive radars are investigated. The potential target detection characteristics of a passive radar using 5G signals for target illumination are evaluated and compared with those of passive radars operating on signals from other transmitters. The 5G signal provides an improved range and velocity resolution than signals from other telecommunication systems.Conclusion. The comparative analysis shows that 5G NR signal transmitters can be used as a promising source of illumination in passive radar systems over relatively small areas.