A call admission control (CAC) protocol is proposed for integrated service WLAN networks in this paper. A popular admission protocol is to admit the incoming calls into the WLAN networks whenever it is available so as to take advantage of low cost and large bandwidth of the WLANs. However, the popular protocol can’t guarantee the QoS of the calls. In order to guarantee the QoS, the proposed protocol maps the characteristics (such as bit rate, bit error rate) of different services into the equivalent spectral bandwidth, and dynamically distributes the equivalent bandwidth to different calls. As a result, the QoS of the calls can be guaranteed, and the spectral efficiency has been developed.