How much did national competition policies converge between 1950 and 2000, and what were the forces behind this? These are the questions the paper attempts to answer, for three countries whose competition policies differed substantially at the outset: Germany, Austria and the Netherlands. The paper measures the degree of convergence of national competition policies, and concludes that there has been convergence towards the stricter EU anti-trust norms. This can be explained by neither negative (`the market') nor positive (`the state') integration, as competition policy is one of the few policy areas where the EU has never explicitly tried to harmonize national legislation. Other forces must have been at work. We investigate the role of various actors, which each play a role in three theories of European integration: institutionalism, which stresses the importance of the central European institutions; neo-functionalism, which focuses on international business; and the epistemic comunity approach, which highlights the importance of transnational expert communities. We find that convergence has been mainly the work of subtle `top-down' pressure from the CEC and the ECJ (`the courts'), combined with the emergence of an epistemic `community' of legally trained officials, which has been a channel for the exchange of information, ideas, solutions and arguments between the systems and levels of law. EU case law provided an important model, experiment and source of norms for this community