Abstract: Packing cases having expansible compartments are described in which the outer wall enclosure of the case is formed with an opening lined with a fastener device, such as a zipper, and an expansible partition of flexible material is secured along its peripheral edges to the edges of the opening, the partition being normally disposed within the main compartment of the case to form an auxiliary compartment separate from but expansible within the main case compartment and closable by the fastener device. In one described embodiment, the opening is formed in an end wall of the case, and the partition is dimensioned such that the expansible auxiliary compartment defined by it is expansible to approximately the full volume of the main compartment.