This paper seeks to examine the structure and functions of the Court of Arbitration for Sport (CAS), so as to highlight, more generally, a number of problems concerning judicial activities at the global level. Section 1 outlines the CAS’ organization and functions, from its inception to the present day. Section 2 focuses on the role of the CAS in creating a lex sportiva, taking into account three different functions: the development of common legal principles; the interpretation of global norms and its influence on sports lawmaking; and the harmonization of global sports law. Section 3 considers the relationships between the CAS and public authorities (both public administrations and domestic courts) to verify the extent to which the CAS and its judicial system are self-contained and autonomous from States. Lastly, Section 4 addresses the importance of creating bodies like the CAS in the global arena, and identifies the main challenges raised by this form of transnational judicial activity. Indeed, the analysis of the CAS and its role as «law-maker» allows us to shed light on broader global governance trends, that affect areas such as the institutional design of global regimes, and, more specifically, the separation of powers and the emergence of judicial activities.