Requirements Engineering is recognized as a crucial part of project and software development processes. This is due to the fact that the different stakeholders involved in a development project have to establish common terminologies as well as goals, scenarios and requirements expressed using these terminologies. Within the Semantic Web initiative various standards emerged for the creation and use of terminologies,
expressed in the shape of semantic networks, taxonomies and ontologies. We develop an approach for semantic based Requirements Engineering. We present an ontology for capturing requirements relevant information. We report about a tool for
semantic based Requirements Engineering and its application in a real-world development project scenario from the eGovernment domain.