ABSTRACT
The outcome of parent training, using the Behavior Management Flow Chart, on mother behavior and on the disruptive behavior of her monozygotic twin boys with Oppositional Defiant Disorder and Attention-Deficit Hyperactivity Disorder was evaluated. Direct observation, telephone interviews, and standardized rating scales showed that parent training reduced oppositional and aggressive child behavior, improved parenting behavior, and reduced maternal stress. A 6-month follow-up revealed stable outcomes. The results are consistent with prior research on behavioral parent training with the Behavior Management Flow Chart. Analyses of the data reveal how the twin boys individually responded to the parent training program and how the mother interacted with her sons differently.