Objectives:The purpose of this study was to evaluate anti-depressive effects of exercise on child and adolescent and its association with brain derived neurotrophic factor (BDNF).Methods: Twenty nine middle school boys (age 13.3±0.7) were divided into two groups, 15 boys for control group and 14 in the experimental group. The control group participated in a regular exercise program, 3 times a week for 15 weeks. During the same period, the experimental group participated in an aerobic exercise program specifically designed to enhance anti-depressive effect of exercise. Serum BDNF level and its performance of each group on the Beck Depression Index (BDI), Children's Depression Inventory (CDI), Screen for Child Anxiety Related Emotional Disorders (SCARED), Aggression Questionnaire (AK-Q), and Stroop task were compared before and after the exercise program.Results: Scores of BDI, CDI, SCARED, and AK-Q were significantly lower in both groups after the exercise programs compared to those before the programs. The Stroop task performances were significantly improved after the programs. However, there were no significant differences between two exercise programs, except SCARED separation anxiety, AK-Q physical, and verbal aggression scores. Also, no association was found between serum BDNF level and anti-depressive effects of exercise.Conclusion: Our preliminary results suggest a possible effect of exercise on depression, anxiety, aggression, and cognition of child and adolescents.