Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 52 1 2014 01 15 49 51 EN Ahmad Ghanizadeh Department of Psychiatry, Research Center for Psychiatry and Behavioral Sciences, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran. 2015 10 11 This study examines the association of father's and mother's age with the severity of inattention and hyperactivity/impulsivity. Participants are 470 children with attention deficit hyperactivity disorder (ADHD) diagnosed according to DSM-IV diagnostic criteria. Moreover, parents reported the severity of ADHD symptoms through completing ADHD checklist. Mother's and father's age was associated with the score of hyperactivity/impulsivity. Lower father's age and advanced maternal age are associated with higher severity of hyperactivity/impulsivity in children and adolescents with ADHD. None of mothers' and fathers' age is associated with ADHD inattentiveness severity in children. Maternal and paternal education levels are not associated with ADHD severity. Older mothers and younger fathers have ADHD children with higher hyperactivity/impulsivity severity. It should be investigated whether the father's and mother's age are risk factors for ADHD. https://acta.tums.ac.ir/index.php/acta/article/view/4736 https://acta.tums.ac.ir/index.php/acta/article/download/4736/4566