A new medium access control (MAC) scheme has been proposed for video service in CDMA systems. We introduce suitable metrics first for video quality rating such as average peak signal to noise ratio (PSNR) and distortion variation. Then, based on these criteria, the effective MAC scheme is obtained for the real video service by taking image characteristics into consideration and modeling the distortion propagation effect due to motion compensation. Unlike the conventional schemes, the new scheme varies the bit error probability (BEP) with the changes of image characteristics. Simulation results show that the proposed scheme utilizes bandwidth more efficiently than conventional schemes do.