One of the most urgent and complex concerns facing the world today is achieving an accessible food supply for a population expected to reach 9.7 billion by 2050. By 2030, 60% of the population will live in urban areas. Community gardens are increasingly seen as a very promising way of ensuring food security, since they help in providing supplementary food for the lowest income groups, making fresh products available and ensure social integration. The aim of this study is to evaluate the importance of implementing community gardens in urban areas, through cases evaluated in Spain and France. The methodology involved interviews with the project leaders supplemented by field visits. The results show that numerous points in common exist between within the two countries, such as the production of organic fruit and vegetables without chemicals, which ensures a certain reduction in costs, combined with the trend towards local production, resulting more sustainable, greener cities. The differences concern the way in which these initiatives are managed, the group responsible for setting them up and how they are subsidized and financed, but these are common within each of the two countries. Among the main conclusions drawn from this study are that, to ensure sustainable cities, community garden projects should be more numerous, as they offer many benefits to the inhabitants and the city itself. Moreover, the need for the contribution of community gardens to the three pillars of sustainable development - economic, social and environmental - are all elements to be considered.