This paper proposes a QoS approach for an adaptive call admission control (CAC) scheme for multiclass service wireless cellular networks. The QoS of the proposed CAC scheme is achieved through call bandwidth borrowing and call preemption techniques according to the priorities of the traffic classes, using complete sharing of the available bandwidth. The CAC scheme maintains QoS in each class to avoid performance deterioration through mechanisms for call bandwidth degradation, and call bandwidth upgrading based on min–max and max–min policies for fair resource deallocation and reallocation, respectively. The proposed adaptive CAC scheme utilizes a measurement-based online monitoring approach of the system performance, and a prediction model to determine the amount of bandwidth to be borrowed from calls, or the amount of bandwidth to be returned to calls. The simulation-based performance evaluation of the proposed adaptive CAC scheme shows the strength and effectiveness of our proposed scheme. Copyright © 2011 John Wiley & Sons, Ltd.