Following the attacks of September 11, 2001, the US authorities decided to collect and retain data on individuals coming to the US by air as a measure intended to increase US security. This act, however, which came into force in May 2004, was found to provide inadequate protection of personal data, and the European Court of Justice required the formulation of a new agreement. In October 2006, the European Union and the United States entered into a new agreement regulating the exchange of passenger name records. In this assessment of the new agreement, CEPS Senior Research Fellow Elspeth Guild addresses the key issues that arise as a result of the new agreement, focusing in particular on the differences between the first and the new agreement that affect the protection of data.