Abstract: An automatic bag system for supermarket check-out counters is disclosed. An open top loading compartment is provided adjacent to the check-out clerk and a roll of plastic material is mounted to feed sheet plastic over the open top of the loading compartment. The loading compartment is provided with transversely opposed vertical slots and guide rollers rotatively secured at the top of the slots. Upon loading purchased items into the loading compartment above the plastic material, the plastic material will be urged interiorly of the loading compartment and will assume the shape of the compartment interior configuration. The guide rollers and the vertical slots cooperate to form left and right vertical seams in the plastic material as the compartment is loaded. The left and right seams are heat sealed upon completion of the loading operations to form a finished plastic package with the purchased items contained therewithin.