This article contrasts species of regulatory and tax arbitrage with the ECJ's approach to abuse of rights. Its aim is to explain the concepts, describe their relationship and identify the legal and policy issues which they raise within the EC legal system. Arbitrage and abuse figure prominently in the ECJ's case-law, especially on the freedom of movement. In its more recent case-law, the ECJ has adopted a more developed approach to abuse of rights by laying down a two-prong test. This article seeks to draw legal and policy conclusions by examining inter alia the virtues and vices of the EC doctrine of abuse of rights. © 2008 The Author Journal compilation © 2008 Blackwell Publishing Ltd.