In this paper, we describe the approach to achieve a high level of interoperability in the eduSource. The eduSource project is a panCanadian collaborative project to create a testbed of linked and interoperable learning object repositories (LOR). Two interoperability mechanisms will support linkage of LORs. A semantic cobblestone supports connecting the LOR into the eduSource network and will provide metadata and ontology mapping facilities. The linkage of eduSource network with other metadata initiatives will be supported via gateway mechanism. Categories and Subject Descriptors H.3.4 [Information Systems]: Systems and Software ? distributed systems, information network, K.3.1 [Computers and Education]: Computer Uses in Education General Terms Management, Design, Reliability, Standardization, Languages Keywords Learning object repositories, Peer-to-peer systems, Learning objects metadata, Ontologies, Semantic web