The European Union bas recently started negotiations on its enlargement with a first group of six countries. This will probably be followed by a second wave of enlargements that would include five or six more countries. A question that can be raised in whether the institutional structure of the EU is ready to cope with an expanded membership. This article aims at analyzing this question as far as the Council of Ministers is concerned. It points at the rising tension between the capacity of the Council to act and the extent of control that each member states can exert on Council decision-making. The IGC that resulted in the Amsterdam Treaty basically failed to resolve this problem. The article looks at the reasons why it failed since these reasons expound the problems the EU will have to face in the near future when preparing its institutions for an expanded membership.