The purpose of this study was to estimate the prevalence of ADHD based on estimation of ADHD rating scale between mother-teacher and teacher-teacher. In total, 491 mothers and 23 teachers rated 689 5-year-old children on the K-ADHDDS. Descriptive statistics, in addition to independent and paired samples t-test were performed. Overall, the percentages of children with ADHD on the rating scale were 3% in combined type, 7.1-8.6% in predominately hyperactive-impulsive type, and 4.2% in predominately inattentive type. Boys tended to show greater tendency of ADHD than girls’: Overall, ADHD tendency in boys was 1.3 times greater than girls. Specially, 2.3 times more for hyperactivity, 1.4 times more for impulsivity, and 3.4 more for inattention. The correlation between mothers’ and teachers’ ratings were .35 for total, .40 for hyperactivity, .24 for impulsivity, and .28 for inattention, and there were no significant differences. Alternatively teacher and teacher ratings were .71 for total, .70 for hyperactivity, .70 for impulsivity, and .67 for inattention, and there were significant differences in inattention subscale(p < .01).