This paper presents the application of ontologies in the field of real estate cadastre. Ontologies can be seen as a form of metadata that provide a higher level of interoperability and integration within the Spatial Data Infrastructure, not only on the syntax level but on the semantic level as well. The application of ontologies in this domain is based on domain ontology for cadastre developed on top of the Land Administration Domain Model defined in ISO 19152 standard. The use of ontologies is shown on the several examples including data integration of the Serbian national cadastre and the INSPIRE cadastral parcels, and integration of OGC based geospatial services and other Web services in cadastral systems. The introduction of semantics in the cadastral systems provide many opportunities in terms of cadastral data and services integration on national and international level, and also in connecting with many other organizations that are users of such systems. These opportunities are reflected in the fact that terms are given well-defined explicit meaning and when based on formal ontology automatic reasoning can be used to infer the new knowledge.