Wage policy and the structure of collective bargaining systems have been neglected in the political and economic discussions that centered around the European Monetary Union (EMU) to an amazing extent. Collective bargaining is one of the very few issues that have been explicitly excluded from the Maastricht treaty as subject of European regulation and only recently, wage policy under the conditions of a European Monetary Union has been considered at closer range. Yet, this has been done without putting the topic into a more general perspective. In this paper, I want to expose a 'theory of optimal wage areas', taking reference to Robert Mundell's seminal paper on 'optimum currency areas'. I want to pose the question whether the European Union can be regarded as an 'optimum wage area' and what will be the consequences for EMU. (author's abstract) / Series: Department of Economics Working Paper Series