A plant for automated packaging of items in cardboard boxes includes a forming station of open sheet boxes starting from a cardboard web, an item introduction system, a box closing station, and a feeding system. A cutting and creasing system at the forming station produces a longitudinal elongate element defining the bottom and top walls and a first pair of side walls of the box, and transverse panels providing the second pair of side walls. A first gluing system bonds the transverse panels to the elongate element by applying hot-melt strips on the side edges of the elongate element, and a pair of suction-cup manipulators applies the transverse panels on the elongate element at the glue strips to obtain a cross-shaped blank. The closing station includes a folding and automatic gluing system that folds and bonds the side walls and the top wall of the box to produce finished packages.