: Using archetypes is a promising approach in providing semantic interoperability among healthcare systems. To realise archetype based interoperability, the healthcare systems need to discover the existing archetypes, based on their semantics; annotate their archetypes with ontologies; compose templates from archetypes and retrieve corresponding data from the underlying medical information systems. In this paper, we describe how ebXML Registry semantic constructs can be used for annotating, storing, discovering and retrieving archetypes. For semantic annotation of archetypes, we present an example of an archetype metadata ontology and