Abstract. As a consequence of the success of the Web, methodologies for information system development need to consider systems that use the Web paradigm. These Web Information Systems (WIS) use Web technologies to retrieve information from the Web and to deliver information in a Web presentation to the users. Hera is a model-driven methodology supporting WIS design, focusing on the processes of integration, data retrieval, and presentation generation. Integration and data retrieval gather from Web sources the data that composes the result of a user query. Presentation generation produces the Web or hypermedia presentation format for the query result, such that the presentation and specifically its navigation suits the user’s browser. We show how in Hera all these processes lead to data transformations based on RDF(S) models. Proving the value of RDF(S) for WIS design, we pave the way for the development of Semantic Web Information Systems.