Since Belgium became a federation in 1995, there have been continuing debates about its future, calls for further regional competences and questions about the role of the federal state. These discussions have led to the reform of 2001, which have increased the powers and financial autonomy of the regions, but institutional reform remained on the agenda and was one of the main objectives of Premier Leterme in 2007. To replace the debate on Belgian federalism and the issue of the respective competences of the central and subnational governments, this paper compares the Belgian institutional system to that of other federations and west European countries. After a brief presentation of the different aspects of federalism in general, the paper turns to the issue of measuring federal institutions for the purpose international comparisons. The Regional Authority Index (RAI) developed by Hooghe et al. (2008a) is the most elaborate and systematic coding scheme of multi-level institutional arrangements. Its data,which covers the period 1950-2006, is used to compare Belgium with the other countries of the EU15 (the 15 member states of the European Union before the Eastern enlargement), Australia, Canada, the United States and Switzerland. This data set allows a comparison of the two aspects of federalism emphasised by Elazar (1987): shared rule, that is, the capacity of subnational governments to make decisions without risking to be overruled by the central government, and shared rule, which is the ability of subnational governments to influence central decision making, most often via intergovernmental relations or a second chamber of parliament based on territorial representation. Finally, this study focuses on fiscal federalism, which is a major issue in the debate on the evolution of Belgian federalism.