the present invention relates to a method and apparatus for making display boxes having windows made of substantially rigid plastic material . the boxes comprise substantially rigid opaque material , such as paperboard , in combination with substantially rigid plastic material . the substantially rigid plastic material includes at least one fold line or groove which cooperates with a fold line in the opaque material when the box is set up . the present invention provides a method and apparatus for making such boxes from a supply of sheets of the opaque material and a supply of sheets of the plastic material . the method comprises the steps of supplying a sheet of opaque material with an opening , positioning a supplied sheet of plastic material into juxtaposition with the sheet of opaque material to cover the opening , adhering the plastic material to the opaque material , and forming groove lines in the plastic and opaque sheets to permit folding of the sheets along aligned groove lines .