A phantom is haunting the EU enlargement process. Some fear that the Balassa-Samuelson (B-S) effect might be a major obstacle for the Central and Eastern European countries (CEEC) to become members of the Economic and Monetary Union (EMU). A review of the relevant literature reveals that most estimations of the B-S effect in the EU acceding countries are flawed by one kind or the other. Either they do not estimate correctly the B-S propositions, or if they measure it they use a variety of measures for the variables needed. Additionally, the B-S effect is only a special case of a broader approach towards equilibrium real exchange rates. Lastly the B-S effect is studied in a CGE multi-country world in order to detect possible spillover effects. After describing the "official" road map towards the EMU, it is concluded that the uncertainties in measuring the B-S are much too high in order to see in it (alone) a major hindrance for the CEEC to become early members of the EMU. Moreover, real exchange rate appreciations that reflect productivity gains in the tradable sector are an equilibrium phenomenon and do not require a policy response. They are a natural phenomena in catching-up countries like the CEEC. Furthermore, the official doctrine for entering the EMU by the EU/ECB only interdicts depreciations but not appreciations for potential EMU members. (author's abstract) / Series: EI Working Papers / Europainstitut