Under what conditions do international governmental organizations (IGOs) cease to exist? Surprisingly, leading theories of international organization rarely address this question. Across the theoretical spectrum scholars assume that international organizations have a high degree of "staying power". Yet reality looks different. More than one-third of IGOs created since 1815 have since died. This article addresses the puzzle of why IGOs cease to exist. Using a combination of standard statistical and survival analysis, I seek to identify factors associated with IGO termination. My analysis is based on a novel dataset coding detailed information on all IGO created since 1815, including their function, membership, and geographic span. Against prevailing theoretical expectations, my analysis demonstrates i) that overall mortality is high among IGOs, ii) that states often prefer to create new IGOs as opposed reforming existing ones, and iii) that having a large and heterogeneous membership is associated with greater survivability. These findings indicate a need for refinement of existing theories of institutional robustness.