The media may influence virtually every health concern that parents and pediatricians have about children and adolescents -- aggressive behavior, drug use, early sexual activity, obesity, eating disorders, school achievement, language development, suicide. Considerable research has been done in the past 50 years that documents the media's ability to teach children and adolescents attitudes and beliefs that may influence their behavior. Media can also be powerfully pro-social. Clinicians need to understand the potential of media to influence young people and ask 2 key questions at health visits: How much entertainment screen time does the child or teen spend per day? Is there a TV set or Internet connection in the child's or teen's bedroom? Public policy suggestions for mediating harmful effects of media are also presented.