Abstract: There is disclosed an electro-mechanical door opening and closing device which is adapted to be retro-fitted onto an existing manually operated sliding door system. The sliding door system has a stationary panel and a movable panel and the system is installed in a wall of a building. A stationary portion includes the stationary panel, the door frame and the building adjacent to the door frame. The device includes a reversible motor, a bracket or handle and a control system. The reversible motor is attachable to one of the stationary portion and the movable panel. The bracket is attachable to the other of the stationary portion and the movable panel. The device includes a threaded rod operably connected to the reversible motor such that the rod may be rotated clockwise and counterclockwise. The rod is also movably connected to the bracket and rotation of the rod clockwise and counterclockwise causes the bracket to move towards and away from the motor thereby opening and closing the sliding panel.