This paper presents automatic generation of the Web Ontology Language (OWL) from an UML model. The solution is based on an MDA-defined architecture for ontology development and the Ontology UML Profile (OUP). A conversion, that we present here, transforms an ontology from its OUP definition (i.e. XML Metadata Interchange ? XMI) into OWL description. Accordingly, we illustrate how an OUP-developed ontology can be shared with ontological engineering tools (i.e. Prot?g?). Categories and Subject Descriptors I.2.5 [Artificial Intelligence] Programming Languages and Software ? Expert system tools and techniques General Terms Design Keywords Ontology, UML Profiles, XSLT, OWL