TDMA based Reliable and Energy Efficient Method for Flooding Wireless Sensor Networks. This invention relates to Wireless Sensor Networks, and more particularly to a TDMA based method of flooding in Wireless Sensor Networks that is reliable and energy efficient. The method comprises of forming a spanning tree of the network using sink of the network as root of the spanning tree with a plurality of non-leaf nodes; and assigning a slot to relay a control message within a control frame to the plurality of non-leaf nodes, wherein length of the control frame is minimized and all nodes of the network receive said control message by end of the control frame.