This paper discusses possible links between monetary arrangements in particular monetary union and economic growth. It is stressed that growth depends ultimately on how the real economy works: there is no monetary magic that can conjure up growth. But monetary policy can contribute to conditions for sustainable growth by securing and maintaining price stability; monetary union might extend this. It might also deepen the single market. The elimination of nominal exchange rate movement among members of the union removes some sources of shock but also some ways of adjusting to shocks. This underlines the importance of other adjustment mechanism especially supply-side flexibility, which is crucial for growth in any event.