Attention-deficit/hyperactivity disorder (ADHD) is a highly heritable neuropsychiatric disorder associated with significant impairments in occu¬pational, academic, neuropsychological, and social functioning. Central nervous system (CNS) stimulants are recommended as first-line medication therapy for children. CNS stimulants include formulations of methylphenidate and amphetamine derivatives and are available in a large variety of immediate- and extended-release preparations. Extended-release preparations are often preferred to limit drug administration during school or work and may help to limit side effects associated with rapid fluctuations in serum concentration. Stimulant medication is by far the most commonly used treatment in managing children with ADHD, 10-20% of those who take such medication do now show clinically significant improvements in their primary ADHD symptom. Even when a favorable response is obtained, some children experience side effects that are of sufficient occurrence and severity to prevent continued use of stimulant medication. In such instances or when families are unwilling to consider a stimulant, non-stimulant medications may be appealing. This review focuses on etiology, assessment and treatment of ADHD with various stimulant and non-stimulant agents.