Abstract: A collapsible cargo container, particular of rectangular or square cross section, has a bottom element, a top element, and side wall elements, which in the erected state for use are joined together by releasable plug-in connectors located in corner pillars at corner regions of the bottom and top elements. In the collapsed state for being shipped empty, the top element is joined to the bottom element with the same plug-in connectors, and the side wall. At least one door fits flush against adjacent side wall elements inwardly of the pillars, to permit flat folding of the container for shipment when empty.