Background: The aim of this study was to evaluate the association of Socioeconomic Status (SES) with anthropomet-ric measures and BP in Iranian children and adolescents. Methods: This nationwide study was conducted in 2011-2012 among 14,880 students, aged 6-18 years, selected by multistage, cluster-sampling method from rural and urban areas of 30 provinces of Iran. Anthropometric indexes and BP were measured by standard protocols and with calibrated instruments. SES was estimated based on family assets and parents " job and education using principle component analysis method. SES was considered as " low " , " intermediate " and " high " in the statistical analysis. Results: Overall, 13486 children and adolescents out of 14,880 invited students (response rate 90.6%) participated in this study. They consisted of 50.8% boys, 75.6% urban residents, with a mean age of 12.47 ±3.36 years. The prevalence of overweight, obesity and abdominal obesity and also mean of all anthropometric measures increased linearly with increasing SES. Inversely, underweight decreased linearly with increasing SES. Association of BP measures with SES was not statistically significant. After adjustment for potential confounders, association of anthropometric measures and BP with SES did not change significantly. Conclusion: We found that obesity, overweight and abdominal obesity was prevalent in high SES group and underweight in low SES group. Our findings serve as confirmatory evidence that contrary to developed countries, in developing countries childhood obesity is more prevalent in families with higher SES.