Web services provide standard means to promote interoperability and extensibility among software applications, as well as to allow them to be combined in order to perform more complex operations. Therefore web services have to be described, published, discovered, invoked and composed. Within this process describing Web services using ontology will enhance service discovery. The "quality" of that discovery depends on the used algorithms and techniques. In this paper we propose a novel approach to enhance web service discovery based on, among others, requesters? preferences. First of all, we propose a way to express preferences of request elements. Then we introduce a matching algorithm that takes into account theses preferences in the discovery process.