Abstract: An order fulfillment method and order fulfillment system includes picking items from inventory according to orders for the items and placing the picked items into picked receptacles. The picked receptacles are forwarded to an unloading station where an identifier of each item is identified at the unloading stating and the identifier of the item married with the transport receptacle into which the item is placed. The transport receptacles are tracked from the unloading station according to the identifier of the item in that transport receptacle and movement of the transport receptacle. This may be accomplished by unloading items to a sorter having sorter locations. Each of the locations has a unique machine location identification. Items are placed from the picked receptacles to the sorter at one of the locations and an item identification is referenced with the machine location identification of the location at which that item is placed on the sorter.