Wireless Sensor Networks (WSNs) have emerged to meet the multimedia requirements in new emerging applications. So it's important for WSN to have an adaptive and energy-efficient TDMA-CSMA based MAC protocol which significantly reduces energy consumption of the network. Here, this study proposes an Adaptive MAC protocol with effective TDMA time-slot assignment and CSMA contention window adaptation for WSN. This approach mainly consists of two parts which are TDMA time-slot assignment and CSMA contention window adaptation. Through TDMA time-slot assignment it is possible for the receiver nodes to re-organize the timeslots among the sender nodes according to their accessible traffic load. Through CSMA contention window, the network can reduce the latency occurring between the nodes during the transmission. © Maxwell Scientific Organization, 2015.