Disclosed are various systems, methods, and other embodiments involving assignment and use of sort bins in a materials handling center. A manifest is generated in a computer system that directs a picking of a plurality of items from a plurality of inventory locations in a materials handling center in fulfillment of a plurality of orders for the purchase of the items. Sort bin assignments are generated in the computer system before picking the items. Each sort bin assignment corresponds to a respective one of the items, and each of the sort bin assignments specifies a corresponding one of a plurality of sort bins designated to coalesce together the items associated with respective ones of the orders for packing. The sort bin assignments are stored in memory for use in sorting the items.