As probably many doctoral theses, the piece that follows has been re-edited and partly rewritten several times. It started off as an analysis of merely Hungarian and EC antitrust matters. While this issue remains in focus, continued research and work at various international institutions drew my attention to important links to processes beyond Hungary and the European Communities. During my internship at the International Affairs Unit of the European Commission’s Directorate-General for Competition, I was involved in competition issues of Central and East European countries, including, but not limited to, Hungary. This confirmed my earlier assumption that, given the rather similar development of those countries and the practically identical text of their Europe Agreements with the European Communities, the domestic and international competition issues they face are also rather similar. My subsequent competition-related work at the Competition Division of the OECD and the WTO allowed me to deal with an even wider range of competition jurisdictions and to realise that transition and developing economies - both in the former Soviet block at large and all over the world - face many similar issues when contemplating the adoption and implementation of competition law and policy. That insight put the thesis in a broader perspective and gave it an additional purpose. When I started this piece, I thought it might be relevant in Hungary and probably in the European Communities. In the light of experience with other transition and developing economies, I now believe that it might be useful in other ways, as well. It might help to better understand the process of transposing the EC antitrust model into other countries, including in Eastern Europe, the Balkans and so-called Euro-Mediterranean countries. More importantly, it is part of a broader and more general picture: how transition and developing economies could develop competition laws and policies most adapted to their situation while not neglecting the model of developed economies’ established competition laws and policies. In particular, in what ways could competition law convergence and co-operation be useful in that process. This latter is the broader topic to which this thesis wishes to contribute by analysing convergence and co-operation in the EC-Hungary context. Indeed, probably few people would decide to deal extensively with the competition law of a relatively small and economically unimportant transition or developing economy, unless the lessons learned in that context can be channelled into the discussion of the aforementioned more general issues. Further, in its limited way, this thesis tries to promote the idea that much more academic attention should be paid to the specific and common issues relating to transition and developing economies’ competition laws and policies - including, but obviously not limited to, the competition law and policy of Hungary.