A novel ID-based channel reservation (IDBCR) multiple access protocol is presented for efficient channel sharing in ad hoc networks. Its flexibly employs request-to-send (RTS) and clear-to-send (CTS) dialogue on a common channel and selects a conflict-free traffic channel to accomplish the transmission of a data packet, based on an ID-based channel selection scheme. The acknowledgment (ACK) packet for the data packet transmission is replied to the sender over another common channel, which effectively eliminates the influence of an exposed terminal problem. Finally, the comparison of the proposed protocol with the CAM-MAC (cooperative asynchronous multi-channel MAC) protocol is provided, and simulation results show that the proposed protocol outperforms the CAM-MAC protocol on a total channel utilization, average channel utilization, and average packet delay.