Introduction: To determine the prevalence of Attention Deficit Hyperactivity Disorder (ADHD)�in the psychiatric history of parents of ADHD children.

Method: With the aid of convenience sampling, parents of 150 children (31 girls and 119 boys)�with ADHD who were referred to the children and adolescent psychiatric clinics of Iran Univer-�sity of Medical Sciences in the years 2002 and 2003 were assessed.  Diagnosis for children was made by clinical judgment and DSM-IV criteria checklist. The history of this disorder in the parents was assessed by DSM-IV criteria checklist and clinical psychiatric interviews. Data were ana-lyzed using descriptive analytical methods.

Results: A positive childhood history of ADHD symptoms was found in 76% of the parents. In 20% of cases both parents, and in 56% one parent had a positive history. The prevalence of fa- thers with a positive history (56%) was higher than mothers (40%).

Conclusion: Hereditary factors may be involved in the etiology of ADHD.