A categorization service is described that automatically categorizes items of interest to a user. The user may possess an item that they wish to offer for sale using the network-based service. The user may prepare an electronic description of the item and submit this item information to a categorization service for categorization. Upon receipt, the categorization service may compare the item information to item category descriptions representing item categories of the network-based server in order to determine category recommendations for the item of interest. The recommended categories are returned to the user to enable the user to assign a category, selected from the category recommendations, to the item of interest.