This paper proposes MAC-MR a new medium access control (MAC) protocol to support mobile nodes and real time Wireless Sensor Networks (WSN) applications. Till now, research efforts to design and implement MAC protocols in mobile WSN are independent from those rhat aim to developp MAC protocols in real time WSN. Our protocol tries to combine these two aspects as nowadays many applications include mobile nodes and packets must reach the sink before a given deadline.\\ MAC-MR is a schedule-based protocol that avoids packet collision and reduces energy consumption due to the retransmission of packets. Nodes are grouped into clusters where cluster heads allocate time slots to their related static nodes as well as mobile nodes. The allocation of these time slots is done according to some rules in order to meet the different real time mobile WSNs constraints.