Parallel rendezvous multi-channel MAC mechanisms are regarded as an efficient method for media access control in cognitive radio networks since they do not need a control channel and use only one transceiver. However, existing parallel rendezvous MAC mechanisms assume that all channels have the same maximum capacity and channel availability for secondary users. In this paper, the authors propose a dynamic parallel rendezvous multi-channel MAC mechanism for synchronized multi-rate cognitive radio networks in which secondary users jump among different channels according to their own distinct hopping sequences and a node can adjust its hopping sequence according to channel conditions, in order to achieve higher system capacity.