To tackle the RRM issue in CDMA systems supporting multiclass traffic, in this chapter we propose a CAC scheme for CDMA systems supporting voice and data services and analyze the Erlang capacity under the proposed CAC scheme. Service groups are classified by their QoS requirements, such as the required BER and information data rate, and grade of service (GoS) requirements, such as the required call blocking probability. Different traffic types require different system resources based on their QoS requirements. In the proposed CAC scheme, some system resources are reserved exclusively for handoff calls to have higher priority over new calls. Additionally, queuing is allowed for both new and handoff data traffic that are not sensitive to delay. As a performance measure of the suggested CAC scheme, Erlang capacity is introduced. For the performance analysis, a four-dimensional Markov chain model is developed. As a numerical example, Erlang capacity of an IS-95B-type system is depicted, and optimum values of system parameters, such as the number of the reservation channels and queue lengths, are found. Finally, it is observed that Erlang capacity is improved more than two times by properly selecting CAC-related parameters under the proposed CAC scheme. Also, the effect of handoff parameters on the Erlang capacity is observed.