Abstract: Improved foldable packaging cases are provided which are particularly suitable, when in their fully opened condition, for use in transporting a plurality of cartons containing fluid products, particularly liquid dairy products such as milk and flavored drinks. The improved cases include structural features that cooperate to provide a case that is readily folded into a compact unit that is especially suitable for opening up to its fully unfolded condition by automatic case opening means, and which when so opened is structured to provide a rigid enclosure that retains a substantially rectangular shape when in use by avoiding both unintentional inward collapsing and undesirable bowing out of the foldable walls.