Abstract: A locking device for securing the doors of a tractor trailer or other cargo container during storage or transport where the locking device is mounted over the latching mechanism of the closing bar movably mounted on the doors of the trailer or container. The locking device includes an enclosure having an outward facing or front panel, side panels, a top panel with two holes formed therein, a partial back panel, and a back side partially open for mounting over the closing bar latching mechanism. The locking device also includes a tubular lock body securely attached to the interior of the partial back panel of the enclosure, and a U-shaped latch rod for inserting through the holes in the top panel of the enclosure into the lock body within the enclosure following the positioning of the enclosure over the latching mechanism of the closing bar.