Summary: The potential scope of an international Arms Trade Treaty (ATT) was a principal subject for discussion during the first meeting of the Open-Ended Working Group (OEWG1) in March 2009. In particular, discussion centred upon the types of equipment and the types of transactions that an ATT should cover. This briefing is intended as a contribution to the debate on one aspect of the former, i.e. the range of military equipment to which a Treaty should be applied. It examines the national lists of military equipment that are currently controlled by a number of national governments with a view to determining whether there exists a common framework on which further discussion could be based.