Attention deficit hyperactivity disorder (ADHD) is one of the most commonly diagnosed behavior disorder of childhood. In recent years, increasing number of preschoolers appear to be manifesting the core symptoms of ADHD. Diagnosis of ADHD in very young children is difficult as high activity level, impulsivity and short attention span are to some extent age appropriate characteristics of normal pre-school children. Concerns both about over-diagnosis and under-diagnosis have been expressed in the literature. Management emphasizing parental counseling, behavior management strategies, and appropriate pharmacotherapy is recommended.