Abstract: A cell door lock for a cell door which pivots on a vertical axis includes a lock casing for mounting adjacent a door jamb associated with the door. A locking barrel is rotatably mounted to the casing for rotation on an axis parallel to the axis of rotation of the door and includes a locking element extending from the casing toward the door for selectively engaging the surface of the door opposite the door jamb for holding the door in a closed position. A movable locking bar co-operates with the barrel for selectively preventing rotation of the barrel to selectively lock the door in its closed position.