Abstract: How can United Nations peacekeeping operations (PKOs) mitigate election violence in war-torn countries? Elections can support the transition from war to peaceful politics. But they also give rise to new uncertainties and may trigger violence. Existing research shows that a higher number of PKO troops help reduce armed conflict risks. Yet, how PKOs and their troops impact election violence has not been systematically examined. I argue that we need to distinguish between PKOs with and without election-related activities to understand the impact of PKO troops on election violence. If a PKO actively assists with organizing and securing elections, a larger number of troops buttresses these efforts through increasing the capacity and credibility of election support provided by the PKO. If PKOs are not involved in the elections of their host country, however, troop numbers neither increase nor decrease election violence. Combining novel data on PKOs‘ election-related activities and existing data on PKO troops, and accounting for endogeneity in both PKO deployment and activities, the analyses of 445 elections in conflict-affected countries (1990-2012) confirm these expectations. The interactive effect between PKOs‘ manpower and their election-related methods holds for different control variable strategies, and when accounting for election assistance by other international organizations. The results imply that the design of peacekeeping is crucial to effectively manage political transitions from war.