Security and trust aspects, perceived as difficult to quantify, have been neglected in various service interactions. However, factors related to security and trust are in fact crucial in the overall value of service quality. A security ontology that enables a quantification of risks related to the usage of Semantic Web services in enterprise information systems was created to meet users’ requirements and enhance Semantic Web services with machine processable security information. This article presents how this security ontology can be integrated into the Web service description and how it enhances the process of Web services filtering.