Abstract.A promising application domain for Semantic Web technology is the annotation of products and services offerings on the Web so that consumers and enterprises can search for suitable suppliers using products and services ontologies. While there has been substantial progress in developing ontologies for types of products and services, namely eClassOWL, this alone does not provide the representational means required for e-commerce on the Semantic Web. Particularly missing is an ontology that allows describing the relationships between (1) Web resources, (2) offerings made by means of those Web resources, (3) legal entities, (4) prices, (5) terms and conditions, and the aforementioned ontologies for products and services (6). For example, we must be able to say that a particular Web site describes an offer to sell cell phones of a certain make an model at a certain price, that a piano house offers maintenance for pianos that weigh less than 150 kg, or that a car rental company leases out cars of a certain make and model from a set of branches across the country. In this paper, we analyze the complexity of product description on the Semantic Web and define the GoodRelations ontology that covers the representational needs of typical business scenarios for commodity products and services.