—Medium access in ad-hoc wireless networks must be performed in a distributed fashion due to lack of coordination between nodes. Specifically, when nodes are capable of receiving more than one transmission simultaneously, the design of distributed medium-access mechanisms that efficiently exploit the receiver’s capability becomes more challenging. Adaptive probabilistic medium access for ad-hoc wireless networks is proposed in this paper. Nodes with data packets to transmit perform an announcement process in order to inform other nodes of their intended traffic. The acquired information through this process about other potential transmitters in the vicinity is then used by the nodes to choose a transmission probability with which they transmit their data packets. The performance of a multi-packet reception capable ad-hoc wireless network under the proposed protocol is analyzed and evaluated numerically and via simulations, and compared with Aloha-type random access.