The vision of the Semantic Web is to give data on the web a welldefined meaning by representing it in RDF and linking it to commonly accepted ontologies. Most formatted data today is stored in relational databases. To be able to use this data on the Semantic Web, we need a flexible but easy to use mechanism to map relational data into RDF. The poster presents D2R MAP, a declarative language to describe mappings between relational database schemata and OWL ontologies. Categories and Subject Descriptors H.2.3 [Database Management]: Languages General Terms Standardization, Languages Keywords Semantic Web, relational databases, RDF data model, mapping