Children from food insecure households are more likely to have substandard food and nutritional intakes, and experience developmental delays, behaviour issues and increased use of health services. In Australia, screening for household food insecurity (HFI) within health services is not undertaken routinely, limiting opportunities to optimise nutrition and healthcare. This research aimed to (a) identify the prevalence, potential determinants and outcomes of HFI among paediatric outpatients in two Queensland hospitals; and (b) identify questions suitable for screening households at risk of HFI. A cross-sectional survey collected data from caregivers of children attending paediatric appointments at two hospitals in Brisbane, Australia (n = 148). Sociodemographic, health and household-related characteristics were collected, and food security status was assessed using four HFI measures. Chi-square, independent t-tests, ANOVA and logistic regression explored associations between HFI and health-related characteristics. A potential HFI screener was identified based on the most frequently endorsed questions from any HFI measure, and its validity was assessed through calculation of sensitivity and specificity. Prevalence of HFI was 41%, with 16% experiencing very low food security. Households with a child of 'fair/poor' health had 5.59 times greater odds of being food insecure than being food secure, compared to households with a child of 'excellent/good' health (aOR 5.59, 95% CI: 1.3-23.5). HFI was also positively associated with household chaos (p = .006). A combination of two questions was identified as a possible screening tool, with a sensitivity of 96% and a specificity of 90%. This study demonstrated HFI may be highly prevalent in a paediatric outpatient population, which may result in difficulties in being able to follow nutrition prescriptions. A highly sensitive and specific two-question screening tool was identified and may assist practitioners in paediatric healthcare settings in identifying clients who are at risk of HFI.