International Competition Law is one of the last white spots of International Economic Law. In the first decades after the GATT had been created the main energies have been spent on lowering tariff barriers to trade. Afterwards, the battle against a vast array of non-tariff barriers started. In the last years, more and more the conviction is gaining ground that also rules for an international regulation of competition should be created. Some proposals made in the recent past are very far-reaching. They are academically interesting but at the same time unrealistic. In this article it is argued that Regional Trade Agreements constitute an interesting testing ground to conceptualize international provisions on competition. Particular attention is paid to the question which role should be attributed to international competition law in areas where a policy of so-called open regionalism is followed (as within ASEAN or AFTA.