Abstract. The increase in popularity of the Internet has lead to the proliferation of heterogeneous information systems that could be better utilized if they operated under a common query interface. The purpose of this paper is to describe the representation formalism of ontologies in an LDAP-based information integration system, and to point out the advantages of such an approach o ver traditional systems. The simplicity, coherence and uniformity of the LDAP model allows us to seamlessly integrate source data, schemata discrepancies, and semantic information under a common framework, that is, by design, able to reconcile integration and data processing issues.