This study is to investigate the effect of music therapy Program on Problem Behaviors and Social Skills Children with ADHD. The participants of the study were first and second graders in B elementary school in J city. They were observed in unsuitable behavioral patterns in school life by their homeroom teachers. Fifteen participants were divided into control and experimental group: The control group was eight and the experimental group was seven. Group music therapy was conducted two times a week for seven-week period. It took 35-40 minutes per therapy after school. Child Behavior Checklist-Korean, Social Skills Rating System, Social Acceptance were administered in pre- and post-stages. For the analysis of the data, Mann-Whitney U test was used. The findings from the research are summarized as follows: 1) The experimental group who was treated in music therapy showed a positive effect on problem behaviors. That is to say, the participants in the experimental group improved in emotional and cognitive stability while they significantly decreased attack behaviors; 2) The experimental group statistically showed significant improvement in their social behaviors compared to the control group. The music therapy group significantly increased social skills such as cooperation, self-assertion, and self-control. However, they did not improve responsibility as social skills in a significant manner; and 3) The experimental group showed higher degree of social acceptance than the control group. However, the result did not show a significant difference between the groups. In conclusion, the study proved positive effects of music therapy on ADHD children's uncarefulness, attack behaviors, and social skills for seven-week experimental period. Key Words： Music Therapy Program, Attention-Deficit Hyperactivity Disorder, Problem Behaviors, Social Skill