Urban agriculture is the growing of plants and the raising of animals for food and other uses, and related processing and marketing activities, within and around cities and towns. Urban agriculture has received increased attention in the past few years from development organisations and national and local authorities in developing countries. With its multiple functions, urban agriculture plays an important role in urban poverty alleviation and social inclusion, urban food security, urban waste management and urban greening. Since 1999, partners of the International Network on Urban Agriculture and Food Security (RUAF Foundation) have been playing a crucial role in improving access to information on urban agriculture and in enhancing the capacities of local authorities, NGOs, farmer organisations and other stakeholders regarding local participatory diagnosis and strategic action planning on urban agriculture. This publication presents the "state of the art" of the development of sustainable urban agriculture and as such indicates progress made since the first major publications on urban agriculture: the UNDP publication "Urban Agriculture" (published in 1996 by Smit et al.) and the DSE publication "Growing Cities, Growing Food: Urban Agriculture on the Policy Agenda" (published in 2000 by Bakker et al).