The wrapping of groups of products positioned according to a determined number of mutually superposed layers is achieved by feeding in succession groups of products firstly into a tubular case made to heat-sealable material and, then, to a first wrapping device when the number of layers is equal to one and to a second wrapping device when the number of layers is at least equal to two; the two wrapping devices being able to wrap each group inside a related wrapping sheet, which is folded substantially in contact with the related group, and which is stabilized by means of sealing operations.