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. While an increasing number of PKOs is mandated to assist elections, there is no systematic study on how PKOs impact election violence. I argue that we need to distinguish between PKOs with and without election-related activities to understand the impact of their deployment on election violence. Only if PKOs actively assist with organizing and securing elections, can they address the election-specific incentives for violence. Using novel data on PKOs' election-related activities and accounting for endogeneity in both PKO deployment and activities, the analyses of 445 elections in conflict-affected countries (1990-2012) confirm this expectation. PKOs only reduce the risk of election violence if they adopt election-specific policies. This finding 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 manage political transitions from war.