Journal of Research in Medical Sciences1735-199512620071202Prevalence of overweight and obesity among junior high school students in a district of Tehran315319ENMaryamAminiDepartment of Nutrition Research, National Nutrition and Food Technology Research Institute, Shaheed Beheshti University of Medical Sciences and Health Services, Tehran, Iran.. maramin2002@yahoo.comNasrinOmidvarMasoodKimiagar2007031020070911BACKGROUND: To determine the prevalence of overweight and obesity among a sample of middle class junior high school students in a district of Tehran and its association with certain demographic and dietary factors this study was carried out. METHODS: Weight, height, waist and hip circumferences were measured and information on two-day food intake and demographics on 398 students aged 10-15 years from district 6 in Tehran were collected. RESULTS: Prevalence of overweight and obesity in the studied girls were 19%, 6.5% and in boys were 14%, 13%, respectively. There was an inverse relationship between numbers of siblings and BMI. Overweight/obese students, bought snacks from school shops more frequently than other students did. CONCLUSIONS: Findings showed that the high prevalence of overweight/obesity can be related to the household size, including the number of siblings and the pattern of snack purchase by the students. KEY WORDS: Obesity, body weight, body mass index, waist-hip ratio, overweight, adolescents.