Through wireless sensor networks (WSN), we can acquire the various interesting event information around sensor nodes through multihop communications. In WSN, there are two types of applications, that is, event or query based. Commonly, in these application, the value on each sensor node is very sensitive to delay or latency. So, it is strongly required to deliver data to sink node within the deadline since data received after the deadline is not acceptable at all in WSN. The good example of application demanding real-time communication in WSN includes tracking of moving object and intrusion detection.However, compared to typical networks, it is very difficult to achieve real-time communication in WSN. Severe constraints such as limited computing power and narrow bandwidth are not suitable to provide real-time communication accordingly. So, a number of important issues and research challenges have to be addressed to provide real-time communication in WSN. Based on this demand, this special issue is planned to contribute to advances in real-time communications in WSN.While considering our objective, editors believe that this special issue provides collection of articles on networking technique in real-time communications. We have selected valuable papers by evaluating several aspects such as relevance to special issue and novelty of solution. The topic of these papers is roughly categorized into the following areas: multichannel transmission, MAC protocol, testbed for routing protocol, and comprehensive survey for real-time in WSN.