In the 1980s evidence of rising levels of hunger was a concern for many, but disputed by some, Americans. Acknowledgement and quantification of hunger was hindered by the lack of an accepted definition and measure of hunger. Qualitative research at Cornell provided a conceptual framework, description, definition and survey items for hunger. The Community Childhood Hunger Identification Project developed an instrument used in numerous communities. Based upon these initiatives, widely accepted definitions of hunger and food insecurity, and the US Household Food Security Module for its measurement, now exist. The module classifies households as food-secure, or food-insecure without hunger or with moderate or severe hunger, and contains household-, adult- and child-referent items. Its inclusion in the Current Population Survey (CPS) since 1995 has yielded annual estimates of food insecurity. A six-item short form of the module, for surveys with severe time constraints, classifies households only as food-secure or food-insecure without or with hunger and contains no child-specific items. Surveys using the 18-item or short-form module can compare results with published national data from the CPS. Information about the module is available at http://www.ers.usda.gov/briefing/foodsecurity and http://www.fns.usda/fsec. Current research on food security measurement includes measurement of individual food insecurity and hunger, module performance regarding hunger duration and frequency, performance of the module in population subgroups, and the effect of translations on module meaning and performance. National surveys in Canada, New Zealand and Australia also have measured food security.