The latest wave of regional organizations may pose a more serious risk of fragmentation in global governance than earlier regional initiatives. Although these new organizations offer additional resources for global ends, the benefits of specialization, and innovation that could improve global governance, they also risk uncoordinated fragmentation, competition that undermines global norms, and a neglect of important global policy aims. Reinforcing global institutions, building consensus on global purposes and a global-regional division of labor, and establishing informal and formal organizational links between regional and global institutions can offset risks and expand the benefits of the new regionalism.