This paper presents a proposal for an open XML standard for the markup of legal documents: METALex. The standard provides a generic and easily extensible framework for the XML encoding of the structure and contents of legal and paralegal documents. MetaLex is first and foremost meant as an interchange format for legal documents. It differs from other existing metadata schemes in two respects: It is language and jurisdiction independent and it aims to accommodate uses of XML beyond search and presentation services.