This is the eleventh in the series on EU Competition Law and Policy produced by the Robert Schuman Centre of the European University Institute in Florence. The volume reproduces the materials of the roundtable debate which examined the enforcement of the prohibition on cartels. The workshop participants - senior representatives of the Commission and the national competition authorities of some EC Member States, renowned international academics and legal practitioners - discussed the economic and legal issues that arise in this particular area, including: 1) unearthing cartels: the evidence; 2) the institutional framework and 3) tools of enforcement.