AbstractThe most popular bibliographical standards, which prescribe the exchange of bibliographical data in machine readable form, are MARC (Machine Readable Cataloguing) and UNIMARC (Universal Machine Readable Cataloguing). This paper presents two schemas, both written in the XML schema language: the UNIMARC format schema and the XML bibliographical records schema. The instance of the UNIMARC format schema is an XML document of UNIMARC format. This schema provides easier updating and adjusting of the UNIMARC format at the national or regional level. It was also the basis for the development of the XML editor for UNIMARC format description. The instance of the XML bibliographical records schema is an XML bibliographic record. This schema provides very thorough control of the contents and structure of bibliographical records, whether they were directly created as XML records or converted to XML from existing UNIMARC records. The validation process is implemented in the Java environment, with the Sun Multi‐Schema XML Validator (MSV) package. The author is aware of the inevitable question of redundant information contained in these two schemas and proposes some possible solutions. Copyright © 2004 John Wiley & Sons, Ltd.