Individual treatment response to behavior modification was examined in the context of a summer treatment program. Four children ages 11 to 12 and diagnosed with attention-deficit/hyperactivity disorder were examined in a BABAB design in which a comprehensive behavioral program was utilized and withdrawn across an 8-week period. Dependent measures included frequency counts of negative behaviors, rule violations in recreational and classroom settings, and academic seatwork completion and accuracy. Results documented the effectiveness of the behavioral intervention with all 4 children. Some children showed consistent responses regardless of setting, while others showed differential responses in classroom and recreational settings. In general, behavior worsened progressively over days during the withdrawal weeks. The second withdrawal of treatment produced deleterious effects for several children that persisted for a time even when behavior modification was reinstated. The individual response patterns of each of the 4 children are discussed.