The research presents a adaptive TDMA slot assignment algorithm, called MDRAND, which is a modified version of DRAND in clustered wireless sensor networks where cluster nodes need its own time to transmit and receive. Priorities will be given to traffic which is real time applications and best effort applications. It utilizes on the requests which will be send by nodes which would be willing to send. Reservation of slots will be done on upon requests. Simulation results show that time complexity and space complexity is (On) which is similar to that of DRAND algorithm.