OBJECTIVES:To compare prevalence estimates of food insecurity using a single-item measure, with three adaptations of the United States Department of Agriculture Food Security Survey Module (USDA-FSSM). METHODS:Data were collected by postal survey, from individuals aged ≥18 years from disadvantaged suburbs of Brisbane, Australia (n= 505, 53% response). Food security status was ascertained by the Australian single-item measure, and the 6-, 10- and 18-item versions of the USDA-FSSM. Prevalence estimates of food insecurity and different levels of severity of food insecurity estimated by each tool were determined. Data were analysed using McNemar's test, polychoric correlation and Rasch analyses. RESULTS:The prevalence of food insecurity was 19.5% using the single-item measure; significantly less than the 24.4%, 22.8% and 21.1% identified using the 18-item, 10-item and 6-item versions of the USDA-FSSM, respectively. Rasch analyses revealed that overall the USDA-FSSM may be a valid tool for the measurement of food insecurity within the current sample. CONCLUSION:The measure of food insecurity employed in national surveys in Australia may underestimate its prevalence and public health significance. Implications for public health: Future monitoring and surveillance efforts should seek to employ a more accurate measure as the first step in recognising the right to food for all Australians.