MIMAS is a national UK data centre which provides networked access to resources to support learning and research across a wide range of disciplines. There was no consistent way of discovering information within this cross-domain, heterogeneous collection of resources, some of which are access restricted. Further these resources must provide the interoperable interfaces required within the UK higher and further education 'information environment'. To address both of these problems, consistent, high quality metadata records for the MIMAS services and collections have been created, based on Dublin Core, XML and standard classification schemes. The XML metadata repository, or 'metadatabase', provides World Wide Web, Z39.50 and Open Archives Initiative interfaces. In addition, a collection level database has been created with records based on the RSLP Collection Level Description schema. The MIMAS Metadatabase, which is freely available, provides a single point of access into the disparate, cross-domain MIMAS datasets and services.