This introduction sets the context of the analysis conducted in this special issue. In particular, it examines the issue of the democratic legitimacy of the European Union (EU) Economic Governance, the role of national parliaments and of the European Parliament in the European integration process. It also addresses the question of throughput legitimacy within the EU that guides all contributions. This serves as basis to study the urgency of the democratic challenge in the EU economic governance, as well as its specificity. After the contributions to this special issue are briefly presented, this introduction examines what they bring to the overall debate on democratic legitimacy in this policy domain, among others in terms of the difficulties that have arisen across Member States. At the same time, perspectives of possible future developments are also spelt out, in particular in the context of an EU-27 post Brexit.