This article attempts to draw the picture of the Committee of the Regions after Treaty of Lisbon and the 2004 and 2007 enlargements of the European Union. The Committee of the Regions has received several new legal tools to influence EU decision taking, such as an increase in mandatory consultation rights and for the first time locus standi before the ECJ. Yet, the main reason to revisit the Committee was to assess the impact of the recent enlargements on its composition.The composition of the Committee has been a thorny issue from the outset. According to some authors it has always been the main handicap of this advisory body of the EU. To what extent have the 2004 and 2007 enlargements upset the delicate balance between the local and regional players in the Committees (if such a balance was there to begin with)? In this study that questions was tackled by using the 'legislative regions' of the Union as a ‘prism for research’. This research approach was based on the fact that the legislative regions were the main driving force behind the Committee’s establishment and on the premiss that their continued interest and support are vital for the 'institutional survival' of the Committee.In a series of interviews with members of the Committee representing ‘legislative regions’ (Belgian and Spanish entities) as well as with members representing local authorities (Dutch provinces and municipalities) the question on the (continued) importance of the Committee as a channel for influencing EU decision taking for the Union’s legislative regions was discussed.