Children with attention deficit hyperactivity disorder (ADHD) have lower diurnal cortisol levels than non-ADHD comparison subjects. Aiming at elucidating the effects of medications used to treat ADHD, we investigated saliva cortisol in children with ADHD: 20 without medication, 147 on methylphenidate, and 21 on atomoxetine. The only significant finding was that children on atomoxetine had higher cortisol levels at bedtime than unmedicated children.