Arms transfer control authorities are in an unenviable position. Great responsibility is implied in each decision they make regarding the authorisation of the export of certain types and volumes of military goods or technology. A decision to deny the requested transfer licence prevents a company from supplying a customer abroad and is bad for business, while a decision to authorise the transfer might result in the goods being used for ill. In an ideal world, arms export control authorities would have at their disposal accurate end-use documentation allowing them to judge whether the intended use is in line with the exporting country’s national laws, as well as regional and international conventional arms control arrangements. In the real world, however, they have all reasons to be aware that the arms may end up being used elsewhere, by others and for other ends. Awareness of the risk that arms transfers may be diverted to other users and uses has become notably more articulated in recent years. A number of high level international initiatives are in the works to mitigate that risk. These seek to improve the reliability of end-use(r) documentation and ensure that relevant information is shared among concerned parties. Before taking stock of these initiatives and outlining their context, this report first presents the state of play of arms export control practices in Europe and the United States. In this process, the report identifies where verification of end-use documentation, post-delivery control and actual end-use monitoring can be improved. It probes the progress made and reflects on what can realistically be achieved on the road ahead.