Abstract: A mailbox charecterized by a tubular container having a flat back face adapted to rest against a door surrounded by a door jamb. The back face extends upwardly into a flat plate which hangs on a door knob. The container has an opening at one end which abuts against the door jamb for closing this one opening. The opening at the other end is provided with a unidirection gate for preventing withdrawal of letters and papers inside the container. Access to the inside of the container is reached when the door is opened.