Introduction Biological diversity is usually associated with wild animals and plants, and there is generally little political awareness of the crucial importance of genetic diversity in agriculture for food security and human survival. As a result, little is being done to halt the rapid erosion of genetic diversity currently taking place in agriculture or to address the emerging problem of restricted access to available genetic resources. This article is about plant genetic resources for food and agriculture and the work being done within the FAO system to establish a regime for the management of these vital resources. Its purpose is to assess FAO’s achievements and identify the limitations in this issue area, with particular focus on the FAO Commission on Genetic Resources for Food and Agriculture (CGRFA). The CGRFA has concentrated on the implementation of the International Undertaking on Plant Genetic Resources for Food and Agriculture (1983), the development of the Global Plan of Action (1996), and negotiations for an International Treaty on Plant Genetic Resources for Food and Agriculture (2001). Its interplay with other international regimes is fundamental to an understanding of its achievements and limitations, and will be highlighted accordingly. First, however, we turn to the structure of the problem, i.e. the challenges facing the CGRFA.