Objectives: The aim of the current study is to test for the association of DRD4 exon III VNTR polymorphism with attention-deficit hyperactivity disorder(ADHD) in Korean children population. Methods: 113 Korean children with ADHD, 102 parents, and 133 control subjects participated with the current study. The distribution of genotypes and alleles of DRD4 exon III VNTR in children with ADHD was compared with that in control subjects. In addition, 69 children with ADHD and their parents were analyzed using the transmission disequilibrium test(TDT). Results: We could not find any significant differences in the distribution of genotypes and alleles at DRD4 exon III VNTR polymorphism between children with ADHD and control subjects. In addition, there was no preferential transmission of long allele of DRD4 exon III VNTR polymorphism. Conclusion: These results suggest that DRD4 is not associated with ADHD in Korean children population.