A technical guide from the World Customs Organisation, depicts the characteristics of the WCO Data Model, a data format (last version: 3.0), based on the UNTDED (United Nations Trade Data Elements Directory), Edition 2005, for the categorisation of messages concerning trade operations. The document illustrates the scope of the Model, its relations with the other international tools, as the Revised Convention of Kyoto, and its alignment with widely used international standards.