Objective: The present study was conducted to examine the effectiveness of behavior therapy (BT) and cognitive-behavior therapy (CBT) on amelioration of attention deficit hyperactivity disorder (ADHD). The effectiveness was studied during the time and within the basic settings in which the core symptoms are manifested. Method: 8 subjects from two special education settings were selected. Multiple baseline design across subjects was utilized. Baseline data were collected through frequent observation of behaviors for each subject. In intervention phase, 4 subjects assigned to BT, and 4 others to CBT programs. Behaviors of subjects were also observed in follow-up phase. Results: The Results obtained from analysis of data points in experimental phases indicated a significant amelioration in symptoms of off-task behaviors. The effects were observed for 3 subjects of BT and 4 subjects of CBT in intervention phase. However, maintenance of effects was not observed in follow-up phase. Conclusion: The findings have implications to study long-term effectiveness of BT and CBT in treatment for the ADHD core clinical symptoms, and generalization of data from school-based setting to home environment.