Objectives：To estimate the prevalence and correlates of children who had Attention Deficit Hyperactivity Disorder (ADHD) in Seoul. Methods：A cross-sectional survey of 2,429 children included in four elementary schools at Seoul. Parents and teachers completed the Korean ADHD Rating Scales (K-ARS) and the Korean version of the Strengths and Difficulties Questionnaire (SDQ-Kr). Child psychiatrists interviewed the children who demonstrated clinically significant scores on K-ARS and SDQ-Kr. Further assessments were conducted with other psychological tests if needed. Results：1) Of 2,429 children, 158 (6.5%) children had ADHD. 2) Compared to controls, ADHD children showed more frequently male preponderance, more single parent family, lower parental education level, more paternal no employment, poorer sibling relationship, fewer number of friends, and lower ability in language and mathematics. 3) In multivariate analysis, ADHD were associated with boys, single parent family, poor sibling relationship, and low language ability. Our stratified analysis by gender, there were association with single parent family and lower language ability in boys, and poor sibling relationship and lower mathematics ability in girls. Conclusion：This study found 6.5% prevalence of ADHD and ADHD were associated with gender, family environment, and academic achievements. Understanding of high-risk children would help in developing an ADHD school mental health program.