The EGDI Metadata Catalogue is the central access point to metadata concerning structured geological data. It provides tools for compilation of those metadata in a standardized format that will allow users to effectively search through the database. In order to make the data discoverable in the most efficient way, the catalogue is fully compliant with international standards and supports the distributed system of metadata administration. Only digital and structured information (spatial datasets or dataset series and spatial data services - WMS, WFS) should be described by metadata in this catalogue. In order to display a metadata record for which an on-line map service is available, the Metadata Catalogue will be integrated into the EGDI Portal. The catalogue enables systematic discovery, viewing and use of geological data across Europe.