This article suggests that subject to the parties' clear agreement to opt for commercial determinations or partisan decision-making, international arbitrators must provide independent, adjudicative services in order to both honor the parties' expectations and contribute to the legitimacy of international arbitration. The article first considers the expectations of the parties and describes how these contribute to a conception of the proper role of international arbitrators. It then describes the adjudicatory functions of international arbitrators and discusses the importance of impartiality. Next it considers potential mechanisms for regulating arbitrator conduct. Finally, it speculates on the future opportunities to promote the integrity of arbitrations and enhance the legitimacy of international arbitration.