Abstract: A spectrum-aware scheduling algorithm is proposed for multimedia applications in cognitive radio system. The algorithm adaptively adjusts the resource share allocated between real-time traffic and non-real-time traffic in varying spectrum environment to provide QoS guarantee for real-time traffic. System simulation based on IEEE 802.22 wireless regional area network shows that the proposed algorithm can provide both better QoS guarantee for real-time traffic and higher system throughput and spectrum utilization compared with conventional scheduling algorithms.