International institutions and the consequences of their interplay are emerging as a major agenda item for research and policy. As governments enter into an ever-increasing number of international agreements, questions arise about the overlap of issues, jurisdiction and membership. Of particular interest to practitioners and analysts is how this mélange of institutions at the international level intersects and interrelates to influence and affect the content, operation, performance and effectiveness of a specific institution, as well as the functioning of the overall global governance context. Biosafety, which is an issue that is relevant to numerous institutions, offers an excellent case study for exploring and applying interplay in practical terms.