Admission control is a key management function in wireless networks, particularly wireless mesh networks (WMNs), in order to support multimedia applications that require quality of service (QoS) guarantees. Even using state of the art schemes to provide QoS, if the amount of traffic in the network is allowed to increase in an uncontrolled manner, network performance will deteriorate significantly degrading the QoS for all network traffic. With admission control, a new flow is admitted only if the QoS requirements of all flows in the network still can be met after the new flow begins. This paper introduces a distributed admission control scheme, called RCAC (routing on cliques admission control) for WMNs. We propose an analytical model that enables computing the appropriate admission ratio to guarantee that the loss rate in the network does not exceed a target value; the model also allows computing end-to-end delay necessary to process flow requests with delay constraints. RCAC achieves scalability since it partitions the network into cliques; only clique heads are involved in the admission control procedure. Simulations, using ns-2, demonstrate that RCAC accepts new incoming flows only when the network target loss rate and end-to-end delay are satisfied and maintains relatively high resource utilization in a dynamic traffic load environment.