Abstract. The Web is moving from being a collection of pages toward a collection of services that interoperate through the Internet. The first step toward this interoperation is the location of other services that can help toward the solution of a problem. In this paper we claim that location of web services should be based on the semantic match between a declarative description of the service being sought, and a description of the service being offered. Furthermore, we claim that this match is outside the representation capabilities of registries such as UDDI and languages such as WSDL. We propose a solution based on DAML-S, a DAML-based language for service description, and we show how service capabilities are presented in the Profile section of a DAML-S description and how a semantic match between advertisements and requests is performed. 1 Introduction Web services provide a new model of the Web in which sites exchange dynamic information on demand. This change is especially important for the e-business community, because it provides an opportunity to conduct business faster and more efficiently. Indeed, the opportunity to manage supply chains dynamically to achieve the greatest advantage on the market is expected to create great value added and increase productivity. On the other hand, automatic management of supply chain opens new challenges: first, web services should locate other services that provide a solution to their problems, second, services should interoperate to compose complex services. In this paper we concentrate on the first problem: the location of web services on the basis of the capabilities that they provide. The solution of this problem requires a language to express the capabilities of services, and the specification of a matching algorithm between service advertisements and service requests that recognizes when a request matches an advertisement. We adopt DAML-S as service description language because it provides a semantically based view of of web services which spans from the abstract description of the capabilities of