The state of the art service search engines allow the users to pick the services they need, based on the quality properties, off ered by these services. To this end, the users should interact with the search engines based on the quality models that are imposed by the engines. This is a signi cant restriction towards making the service-oriented paradigm attractive to the general public. In this paper, we propose an approach that allows a user to specify his perception of quality in terms of a simple, user-de fined quality model. The proposed approach automatically maps the user-defi ned quality model to the search engine's quality model. This mapping forms the basis for ordering, grouping and, in general manipulating, the results of the user's service discovery requests.