Recent advances in wireless technology have brought us closer to the vision of pervasive wireless sensor networks. In sensor networks, the nodes have limited energy resources and the applications generally demand timely delivery of the packets. Therefore, high energy efficiency and reduced latency are of paramount importance. The medium access control layer plays a crucial role in managing the energy spent on communication and keeping the latency in check. In this paper, a real time wireless media access control protocol based on earliest deadline first scheduling scheme is proposed. Unlike its predecessors, this new protocol is applicable to both event-driven and clock-driven nodes with salient features being high energy efficiency and priority based latency. We establish the improved latency performance over carrier sense multiple access protocol, through simulation of wireless sensor network in network simulator-3. Then, we present a mathematical model to obtain the lower bound on the fraction of energy saved by the use of the proposed protocol as opposed to existing protocols. This improvement in latency performance facilitates an increase in cluster size and energy efficient communication ensures increased lifetime of the sensor network, which makes our protocol a promising choice for the future wireless sensor networks. © 2013 IEEE.