A method of filling orders and order fulfillment system includes storing inventory receptacles in an automated warehouse, some having a plurality of different types of inventory items. A queue of orders is maintained in a computer system, each including at least one inventory item. Each order is selected from the queue and assigned to a pick station. The computer system retrieves inventory receptacle(s) from the automated warehouse for the selected order and supplies the receptacle(s) to the pick station. The computer system identifies to an operator which inventory item is to be segregated with the selected order in at least one put receptacle. One or more of the put receptacles receives inventory items for at least one individual order and is directed to a secondary order processing station where items are separated into individual orders. The operator may be provided the capability to consolidate inventory items from inventory receptacles while picking orders to consolidate partially filled inventory receptacles in a consolidated inventory receptacle.