The thesis scrutinizes the effects of the Council Presidency on legislative decision making in the European Union Council of Ministers. The rotating Council Presidency has been one of most prominent topics of discussion in the debate on institutional reform. So far, however, a comprehensive evaluation of the effects of the Presidency is missing. The thesis addresses two questions: 1. Does the Council presidency have an impact on legislative activity in the Council? 2. Does the Council presidency gain disproportional benefits from the policies agreed upon during its term in office? The methodology used in the thesis consists of an exploratory case study, secondary analysis of the Decision-making in the European Union (DEU) data set, and statistical analysis of an original data set covering legislative activity from 1984-2003. It presents evidence for an effect of the Presidency on both legislative activity and decision outcomes.