A motor-driven sliding door or window comprising: - a fixed frame; - a sash which slides horizontally relative to the frame, between an open position and a closed position; - at least one carriage (3, 4), associated, in use, on a lower crosspiece of the sash and resting on a horizontal base track to allow the sliding of the sash in both the opening and closing directions; - locking / unlocking elements, located on operating rods which slide along at least one vertical upright of the sash; the locking / unlocking elements interacting with corresponding striker elements positioned on the frame fixed at least in order to lock/unlock the sash between the closed position and the open position and vice versa; - a control unit composed of a kinematic unit connected, on one side, to the operating rods and, on the other side, to an activating element for controlling the sliding movement of the rods, in both directions, and allow the configurations for opening and closing the sash; the control unit comprising a box-shaped body positioned inside the vertical upright of the sash; the box-shaped body housing the kinematic unit connected, using a drive element, to the operating rods and an element motor-driven by a source of outside energy, defining the activation unit, connected to the kinematic unit for activating the operating rods by external control; characterised in that the kinematic unit has elements for connection / separation between the drive element and the motor-driven element to allow, when required, an emergency manual movement of the rods using a shaft of a handle connectable, from the outside, to the drive unit through a cavity made on the vertical upright of the sash; the connecting / separating elements being movable between a connected position between the drive unit and the motor-driven element, and a separated position between the drive element and the motor-driven element which can be activated, in use, at the inlet of the shaft of the handle. - a fixed frame; - a sash which slides horizontally relative to the frame, between an open position and a closed position; - at least one carriage (3, 4), associated, in use, on a lower crosspiece of the sash and resting on a horizontal base track to allow the sliding of the sash in both the opening and closing directions; - locking / unlocking elements, located on operating rods which slide along at least one vertical upright of the sash; the locking / unlocking elements interacting with corresponding striker elements positioned on the frame fixed at least in order to lock/unlock the sash between the closed position and the open position and vice versa; - a control unit composed of a kinematic unit connected, on one side, to the operating rods and, on the other side, to an activating element for controlling the sliding movement of the rods, in both directions, and allow the configurations for opening and closing the sash; the control unit comprising a box-shaped body positioned inside the vertical upright of the sash; the box-shaped body housing the kinematic unit connected, using a drive element, to the operating rods and an element motor-driven by a source of outside energy, defining the activation unit, connected to the kinematic unit for activating the operating rods by external control; characterised in that the kinematic unit has elements for connection / separation between the drive element and the motor-driven element to allow, when required, an emergency manual movement of the rods using a shaft of a handle connectable, from the outside, to the drive unit through a cavity made on the vertical upright of the sash; the connecting / separating elements being movable between a connected position between the drive unit and the motor-driven element, and a separated position between the drive element and the motor-driven element which can be activated, in use, at the inlet of the shaft of the handle.