For impact evaluation and for planning and targeting decisions, local organizations in developing countries need tools for assessing household food security that go beyond measuring food availability to include access to food and perceptions of food insecurity. This paper explores the potential for developing direct measures of household food security that include such components and that are based on an in-depth understanding of the experience of food insecurity at the household level. This process was used successfully to develop the US Food Security Measure. The US approach and examples of efforts in developing countries are reviewed, along with relevant conceptual and measurement issues. The potential portability and challenges to use of the US approach in developing countries are discussed. The elements needed to apply this approach are outlined, along with operations research needed for developing such experientially based measures.