This paper describes Save the Children Fund-UK´s Food Economy Approach to analysing household food security, adopted by the organisation in the early 1990s. The paper details the way in which the access of individual households to food, both in normal and bad years, is identified and quantified. The paper examines the conceptual background to the model, asking what is the food economy approach?, what is it used for?, how does it work? and who does what?. It goes on to detail the development of the baseline picture, how different families in a particular food economy area normally obtain food and non-food income. Information gathering, quantification and calculation methodologies are discussed with the aid of pie-charts and tables. Three case studies examine the application of the approach in southern Sudan, northern Kenya and Rwanda.