The number of children diagnosed with attention deficit hyperactivity disorder (ADHD) is rising. It is now considered the most common neuropsychiatric syndrome in US school-age children, affecting 3% to 5%, or approximately 2 million children. ADHD is a chemical imbalance in the brain resulting in inappropriate degrees of inattention, hyperactivity, and impulsivity; these symptoms must be present prior to age 7. ADHD is difficult to diagnose as it is linked to many other conditions such as learning disabilities, conduct disorders, bipolar disorders, and manic-depressive illnesses. The authors offer information on behaviors signaling the need for referral in very young children and describe the positive and negative effects of common medications. They suggest specific behavioral coping strategies for both home and group care settings.