Introduction: Measuring food insecurity has been an ongoing challenge to researchers. This study was carried out to assess the validity of the Household Food Insecurity Access Scale (HFIAS) in measuring household food insecurity in an urban area of Varamin in 2009. Materials and Methods: In this cross-sectional descriptive study, 400 households from different parts of Varamin, a city south of Tehran, were selected by the multi stage cluster sampling method. Household food security was measured by the 9-item HFIAS questionnaire that asks whether a specific condition associated with the experience of food insecurity ever occurred during the previous 30 days. Based on the HAFIAS questionnaire score, households were categorized in 4 groups according to access to food food secure, mildly, moderately and severely food insecure access. In the second stage of the study, 30 households were selected from each group. Results: Food security was observed in 21% of households. Mildly, moderately and severely food insecure access was 46.5, 25 and 7.5 %, respectively. Based on the responses to the 9 questions of the HFIAS questionnaire, perceptions that food is of insufficient quality (72%), two main factors emerged from the rotated principal component factor including: 1) Insufficient food quality and 2) Insufficient food intake. Both factors explained 77.5 % of the total variance. HFIAS has good internal consistency (Cronbach’s α= 0.95). Conclusion: Food insecurity was observed in households in this urban area of Varamin. The HFIAS measurement instrument shows acceptable validity and reliability in measuring food insecurity among households.