An opening/closing device for a double flap door of an item of furniture, wherein the top part and the bottom part of the door are not hinged to each other. The device is connected to the furniture item to cause the top part of the door to rotate with respect to the furniture item and an articulated quadrilateral causes the bottom part of the door to rotate with respect to the top part concomitantly with the rotation of the top part of the door with respect to the furniture item. The articulated quadrilateral includes a first and a second arm each having one end hinged to the bottom part of the door and the other end hinged to the device.