Attention-deficit hyperactivity disorder (ADHD) is a neurobehavioral disorder with an onset of symptoms before 7 years of age, often starting as early as the preschool years. The off-label use of methylphenidate (MPH) for 3- to 6-year-old preschool children with ADHD is being more common, although MPH is not licensed for use in children younger than age 6 years, in most countries. Despite the limited data, the review of the literature suggests that MPH meets evidence based criteria as beneficial and safe for carefully diagnosed ADHD preschool children. Carefully monitored administration of evidence-based psychotropic medication in preschool children with ADHD may be indicated if psychosocial treatments are ineffective.