This article offers a reflection on asymmetry as an instrument of differentiated integration in the current phase of the EU integration process. As for the structure, this work is divided into four parts: First, I shall clarify what I mean by asymmetry as an instrument of integration relying on comparative law. This comparative exercise is particularly useful because it allows us to acknowledge the strong integrative function performed by asymmetry in contexts different from but comparable to the EU system. Second, I shall look at EU law and recall the main features of asymmetry in this particular legal system. In the third part of the article I shall look at the implications of the financial crisis, which has increased the resort to asymmetric instruments. In the last part I shall deal with some recent proposals concerning the differentiated representation of the Eurozone. The idea of differentiated integration and that of asymmetry have been extended and adapted to many different processes by scholars over the years, but to avoid misunderstandings I would like to make clear that in this work I shall analyse those forms of asymmetries that are allowed and carried out only when respect for an untouchable core of integration is guaranteed. This is crucial to conceive asymmetry as an instrument of integration.