The role of UN peacekeeping missions has expanded beyond the traditional tasks of peacekeeping to include a wide range of political, economic, and humanitarian activities. While such expansion indicates an improved understanding of the complexities and challenges of post-conflict contexts, it also raises questions about whether UN peacekeeping missions are equipped to handle peacebuilding tasks. Evidence from a study of the peacekeeping mission in Sierra Leone suggests they are not. This article argues that peacekeeping missions are a poor choice for peacebuilding given their limited mandates, capacity, leverage, resources and duration. Peacekeepers should focus on peacekeeping, by which they can lay the foundation for peacebuilding. Peacebuilding should be the primary task of national governments and their populations.