The data aggregation scheme of wireless sensor networks (WSNs) can reduce the number of transmitted packets by aggregating multiple packets in one packet; thus, it can reduce energy consumption at the same time. However, the energy consumption of idle listening in WSNs remains dominant in the total energy consumption for WSNs. Therefore, the duty cycle MAC protocols have been used to reduce idle listening. However, if aggregation is used on duty cycle MAC protocols, it has very low performance caused by the latency of the sleep-wake scheduling. The goal of the present work is to design energy efficient event-aware MAC scheduling that can be used by a data aggregation technique. In order to aggregate the packets spatially and temporally, two corresponding mechanisms are proposed: the event-aware and energy-aware routing (EE routing) protocol at the routing layer, and the aggregation scheduling MAC (A-MAC) protocol at the MAC layer. The EE routing protocol chooses the best path for better aggregation and for energy balance in WSNs. The A-MAC protocol adjusts schedules to aggregate more packets while maintaining a low latency. The performances of the proposed protocols are evaluated through ns2 simulations. The results indicate that the proposed protocols reduce energy consumption by 80-90% and have balanced energy consumption while maintaining similar latencies and aggregation rates compared with previous aggregation protocols. (C) 2010 Elsevier B.V. All rights reserved.