Abstract: Disclosed herein is a method and apparatus for forming corrugated cartons with plastic bag liners therein from conventional flat unformed cartons. The apparatus is comprised of an assembly for spreading the forward flaps of the cartons and pressing the flaps back onto the sides of the cartons; conveyor systems for continually bringing a carton and bag liner together such that the forward folded flaps of the carton are disposed within the bag; and a forming station where the cartons are opened into a rectangular configuration and a bag, a portion of which is disposed about and held by the folded flaps of the carton, is forced back through the carton whereupon the bottom flaps of the carton are folded into the closed position and sealed, thereby continually forming open ended corrugated cartons having plastic bag liners disposed about the interiors thereof.