This article analyses the influence of EU law on hybrid financial instruments (HFIs). Part 1 addresses the impact of primary EU law on HFIs, identifies the applicable freedom, discusses the influence of the TFEU on the approach of Member States to classification and taxation of HFIs and addresses the conformity of coordination rules with EU law. Part 2, to be published in European Taxation 12 (2013), analyses potential justifications and the proportionality test.