Introduction: gargantuan effort required to feed cities has played a central pat in the rise and fall of urban civilizations from time of ancient romans to the present day. 20th century global changes placed unprecedented pressure on cities and their food systems o. Intensive rural to urban migration, loss of farmland, rise of technology. Food is reappearing on the agendas of a growing number of municipal governments and emerging as a pressing concern for many urban dwellers. Food systems includes all of the activities and processes people produce, obtain, consume, and dispose of food o. Inputs and outputs that make the system run. Feeding twenty-first centruy cities: municipal governments in cities worldwide increasingly developing food policy commitments. Brazil implementing policies based on the principle of food security as a right of citizenship. Rosario, argentina recognized for its food policy development with a united nations best practice award for its urban agriculture programmed.