The research presented in this paper has the objective to develop a process for transforming an enterprise model into an enterprise ontology. The focus is to preserve as much as possible of the semantics and the information content. A suitable approach to base the development of the transformation process on has been selected in a comparative study of three different approaches. The selected approach uses a meta-model to support the transformation process. The outcome of the research is both the improved transformation process based on the meta-model based transformation approach and a tool named EM2EO for processing the transformation. The tool reads an XML-file containing an enterprise model and produces an OWL-file containing the enterprise ontology.