The worldwide growth of urban population questions the alimentary function of agriculture near the cities. In developing countries, urban agriculture products are increasingly contributing to urban diets and in northern countries, the crisis of the "globalized agri-food system" (Morgan & al, 2006) increases the urban dwellers' interest for local products. This persistence and/or renewal of the alimentary function of urban agriculture nevertheless addresses main questions for agronomic research (i) how to quantify the alimentary function of urban agriculture, when basic statistical data are scarce (ii) what are the place of short supply chains in this alimentary function, the geographical proximity between consumers and producers leading to different forms of relationships (iii) what are the specific risks that urban proximity implies on urban agricultural products? With the crosses examples of three research programs, two in Madagascar and one in the Ile de France Region, near Paris, we show that multi-disciplinary approaches are necessary to assess these points. The topic of alimentary function of urban agriculture needs more research to deal with a difficult but very up-to-date problem.