This paper examines the progressive steps of convergence of antitrust enforcement and regulation in Europe. As far as competition law enforcement is concerned, both classical essential facilities remedies and recent changes giving to the Commission and to NCAs the power to accept firms undertakings represent clear steps toward a regulatory activity. This legal development is tantamount to a new power of defining the set of positive economic behaviours a firm can adopt, a type of power previously reserved only to legislative or regulatory bodies. Furthermore, in some regulated sectors, like Electronic Communications, the European regulatory framework is more and more based on competition law and economics principles. These evolutions could possibly rise different kind of problem in the enforcement of competition law and economic regulation. Therefore, they also hint to a possible new institutional frameworks for antitrust and regulators maybe more adapt to the present configuration of powers and duties.