Corrugated Boxes Corrugated boxes are a type of container used in shipping and storage that are ubiquitous across thousands of industries. Although people often refer to them erroneously as cardboard boxes, they are made of corrugated materials. Most typically the corrugated–meaning fluted, rippled or ridged—material from which they are made is corrugated fiberboard. This consists of two flat sheets sandwiched above and below a corrugated sheet in layers.