CONTEXT: Achieving successful eradication of a disease requires global cooperation to obtain a shared goal. Coordination of the endgame may seem an obvious requirement for success, but that does not ensure that cooperation will occur. OBJECTIVE: To analytically explore the need for cooperation to maintain global polio eradication specifically related to creation of a global polio vaccine stockpile and coordination of oral poliovirus vaccine (OPV) cessation. DESIGN: Using risk and decision analysis and game theoretical concepts, we modeled the importance of global cooperation in managing the risks associated with polioviruses for a time horizon of 20 years after successful global disruption of circulation of wild polioviruses. RESULTS: Countries may wish to avoid the financial costs of vaccination and risks for vaccine-associated paralytic polio following eradication of wild polioviruses, which may lead them to reduce their use of OPV. However, reducing or stopping vaccination too soon and without coordination poses serious risks, including the possibility of reimportation of wild polioviruses and the possibility of vaccine-derived polioviruses. Analysis of the risks for potential outbreaks suggests the need for creation and maintenance of a global stockpile of vaccine for outbreak response. Game theoretical considerations show that coordination of OPV cessation optimizes expected costs and risks globally, despite the potential perceived incentives for countries to stop OPV earlier or later than other countries, or to continue OPV use indefinitely. CONCLUSIONS: This article makes the strong case for global cooperation on risk management and suggests that even though individual countries may perceive their own risks as small, risks at the global level warrant cooperative action and coordination of OPV cessation.