Despite high heritability, no research has followed children with ADHD to parenthood to study their offspring and parenting behaviors. Given greater prevalence of ADHD in males and lack of research involving fathers, this study evaluated offspring of fathers with and without ADHD histories for ADHD and disruptive behavior and compared fathers’ parenting behaviors. Male fathers (N = 29) from the Pittsburgh ADHD Longitudinal Study (PALS) participated with their preschool-aged offspring. Fathers completed self-reported measures, and father-child dyads completed an interaction task. ADHD offspring had elevated ADHD symptoms and behavior dysregulation. All fathers displayed positive parenting. ADHD fathers reported lower supportive responses to their child’s negative emotions than comparison fathers, yet rated their parenting as more efficacious. ADHD offspring were distinguishable as early as age 3; thus, earlier diagnosis and intervention may be feasible for this at-risk population. Future research should investigate the acceptability and efficacy of parent training for fathers with ADHD.