Virtually all multilateral agreements provide for a treaty secretariat to help governments coordinate their efforts. Andresen and Skjærseth (1999: 2) define a treaty secretariat as a specific type of an international organization ‘established by the relevant parties to assist them in fulfilling the goals of the treaty’. Such secretariats take shape as international bureaucracies that are being operated by international civil servants. So far, little attention has been paid to their specific role in international governance (see Bauer 2006 and Sandford 1992, 1994 for exceptions). Commonly treaty secretariats are perceived as a minor feature of the wider regime that provides the norms, rules and procedures for international cooperation. To better understand the specific functions, capabilities and roles of these bureaucracies in international governance we compare and discuss the influence of three treaty secretariats in the environmental realm: the United Nations Framework Convention on Climate Change (UNFCCC), the United Nations Convention to Combat Desertification (UNCCD), and the Convention on Biological Diversity (CBD).