Urban and peri-urban horticulture (UPH) is currently a subject of passionate debate regarding how viable it is, how efficient it is compared to rural production in supplying food to cities, and whether the State should protect it from urban expansion. The debate is not, however, being supported by reliable data on the relative contribution of UPH to urban food consumption and income, as compared with other sources of food and income supply. This paper has drawn on the relevant data on the origin of urban food products from consumption and market surveys, and also from surveys and case studies of farmers' strategies and economic results in various cities in Africa and Southeast Asia. The undeniably patchy results nevertheless show the importance of urban agriculture in two areas: overall supply of the most perishable vegetables, namely, leafy vegetables; and complementarity of UPH with rural vegetable production. The results also show the specific contribution of UPH in the supply of vegetables with specific food safety characteristics, in particular organic vegetables, because when the production of these types of vegetables is combined with direct sales between producers and consumers, the consumers gain a certain level of responsibility in the production process. UPH contributes to livelihoods in a variety of ways, from the unique provision of incomes to urban households with few alternative sources, to an additional source of cash to urban entrepreneurs and civil servants. This paper highlights the need for additional research in economics on UPH in Africa. The available data on food and economic contribution of UPH are incomplete and need to be updated, and comparisons need to be made between cities to understand the reasons for differences. There should be more systematic comparison between UPH and rural horticulture in terms of income generation, price of vegetables, and labour use and energy use. The economic advantages of a multifunctional UPH should be eval