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 .