Objective: The present study was designed to determine household food security status and factors associated with food insecurity among high-school students in Esfahan, Iran. Design: Cross-sectional surveys. Setting: The present study was conducted in autumn 2008 in Esfahan, Iran. The samples were selected using systematic cluster sampling. Socio-economic questionnaires, food security questionnaires and FFQ were filled out during face-to-face interviews. In addition, data on participants' weights and heights were collected. Subjects: A total of 580 students (261 boys and 319 girls) aged 14-17 years from forty high schools in Esfahan, Iran, were selected. Results: The prevalence of household food insecurity according to the US Department of Agriculture food security questionnaire was 36?6 % (95 % CI 0?33, 0?40). Food insecurity was positively associated with number of members in the household (P , 0?05) and negatively associated with parental education level and job status and household economic status (P , 0?05). Moreover, students living in food-insecure households more frequently consumed bread, macaroni, potato and egg (P , 0?05), while they less frequently consumed rice, red meat, sausage and hamburger, poultry, fish, green vegetables, root and bulb (coloured) vegetables, melons, apples and oranges, milk and yoghurt (P , 0?05). Conclusions: Food insecurity was prevalent among households in Esfahan, Iran, and food security status was associated with socio-economic factors. Students who belonged to food-secure households more frequently consumed healthy foods (except sausage and hamburger), whereas those living in food-insecure households more frequently consumed cheap foods containing high energy per kilogram. The present study suggests that intervention programmes be designed and carried out. Keywords Food securityEsfahan High-school students USDAThe concept of food security includes problems with the quantity of available food, uncertainty about food supply and experience of hunger in life (1,2) . Food insecurity is prevalent in both developed and developing countries, affecting 6-73 % of the general population (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16) . It has considerable health impacts on the physical, social and psychological status of individuals suffering from food insecurity. It also affects quality of life (17) . Various techniques and methods have been used to measure food insecurity in many countries (18)(19)(20) .The aim of the present study was to determine household food security status and factors associated with food insecurity among high-school students in Esfahan, Iran. Methods Data collection and subjectsThis cross-sectional study was conducted in autumn 2008 with 580 students (261 boys and 319 girls) from forty high schools in Esfahan. The average age of students was 15?7 years (range: 14-17 years), and the exclusion criterion was suffering from metabolic disease. The sampling method used in the present study was systemic clustering. Selection of schools and classes was ca...