Since the turn of the century, results orientation and performance measurement have become buzzwords in development aid. Bilateral donors are increasingly concerned about the effectiveness of core-funded UN specialised agencies, funds and programmes, through which they channel a substantial part of their funds. While the logic for increased monitoring is clear, it is less evident how to assess this information for purposes of accountability, performance-based funding and governance. This article describes the general evolution in this area and discusses two major initiatives to harmonise and align bilateral assessments, using case-study material from three bilateral donors (Belgium, the Netherlands and the UK) with clearly diverging performance-management cultures, and exploring the extent to which they rely upon joint and aligned initiatives.