— In this paper, we study the voice and data service provisioning in an integrated system of cellular and wireless local area networks (WLANs). To maximize the overall resource utilization of the integrated system, complementary quality of service (QoS) support capabilities of the two networks are exploited to serve voice and data traffic. As an essential resource allocation aspect, admission control can be used to properly admit voice and data calls to the overlaying cellular cells and WLANs. In this study, a generalized admission scheme is analyzed to investigate the dependence of resource utilization on admission parameters, which vary with user mobility and traffic variability. By applying an effective QoS evaluation approach, the admission parameters can be determined using a search algorithm.