The Food Security and Agricultural Projects Analysis Unit (ESAF) of FAO has undertaken a number of pilot studies to develop a methodology for understanding why certain groups of people are vulnerable to becoming food insecure. The studies use the sustainable livelihoods approach adopted for food security analysis and are primarily based on qualitative information collection. The objective of these studies is to inform policy and programming decisions for reducing vulnerability to food insecurity. Drawing from these experiences and those of other FAO units involved in similar work, this paper identifies key lessons learnt and makes recommendations for strengthening future work on food security and vulnerability analysis.