The purpose of this study was to examine the effects of sandplay therapy for a 7-year-old boy with problems of attention deficit and aggression. The case was conceptualized from the perspective of the objective relation theory and sandplay therapy was planned to address the client’s presenting emotional and behavioral problems. A total of 13 sessions were given to the child over a 10-month period and sandplay themes and mother-reports of child emotional and behavioral changes were analyzed as indices of therapy progress. For mother-reports of child emotional and behavioral changes, an interview was made with child parent immediately after every session. The results are as follows: First, the themes of play were changed from wounding themes to healing themes as the therapy progressed. Second, client’s relationships with mother and peers were improved through the therapy. Third, client’s aggressive behaviors in daily life disappeared after all. The client became active in peer interactions and enjoyed his social activities such as sports, drawing, and learning activities. This case suggests that the sandplay therapy is an effective method in changing children with aggressive behaviors.