With its mandate to work on natural resource management; food security; and livelihoods; and its attention to the social, economic, and environmental dimensions of sustainable development, the Food and Agriculture Organization of the United Nations (FAO) has played a leading role in sustainable mountain development for many years. In 1992, the FAO was appointed Task Manager for Chapter 13 of Agenda 21 (Managing Fragile Ecosystems: Sustainable Mountain Development) and acted as the lead agency for the International Year of Mountains in 2002. The FAO hosts the global Secretariat of the Mountain Partnership and, from 2003 onward, has also been mandated by the United Nations General Assembly to lead observance of the International Mountain Day, every year on 11 December. Over time, the FAO has progressively built up a conceptual and operational framework that links sustainable mountain development to forest hydrology and watershed and risk management. This Platform Statement provides an update on the FAO's regular program on sustainable mountain development, watershed management, and forest hydrology, which includes normative work, a strong field program, and support to international processes. Further, it summarizes the latest achievements of the Mountain Partnership. [ABSTRACT FROM AUTHOR]