Like tariffs and other border measures, national regulatory barriers impede international trade. Unlike tariffs, however, such barriers usually indicate an important domestic policy choice. This conflict of interest has emerged as a crucial issue in international law, particularly with regard to services, such as telecommunications and health services. This study is the first to analyze the potential impact of incompatibilities between national regulatory regimes and the rules and obligations imposed by the General Agreement on Trade in Services (GATS). The author investigates such relevant concepts as the following: the political and ideological dynamics of GATS negotiations; services trade liberalization in regional integration systems, particularly in EC law; policies common to diverse national regulatory systems; the notions of deregulation and privatization; the human rights implications of international trade law; the GATS obligations of market access, national treatment, and most-favored-nation treatment; the role of the WTO s dispute settlement organs; and GATS transparency obligations.