There are a large number of metadata standards and initiatives that have relevance to digital preservation, e.g. those designed to support the work of national and research libraries, archives and digitization initiatives. This paper introduces some of these, noting that the developers of some have acknowledged the importance of maintaining or re-using existing metadata. It is argued here that the implementation of metadata registries as part of a digital preservation system may assist repositories in enabling the management and re-use of this metadata and may also help interoperability, namely the exchange of metadata and information packages between repositories.