School-age children spend more time watching television than in any other activity except sleeping. Although some studies have suggested that watching educational programs can have positive effects on learning and behavior, numerous studies have found an association between television viewing and negative childhood outcomes. This study finds that children who watch more than three hours of television a day, who do not communicate very well with their parents, and whose parents know few or none of their friends have greater levels of externalizing (acting out) and internalizing (i.e., depression or anxiety) behavior problems. Moreover, the combination of frequent TV viewing and low levels of parental involvement is related to particularly elevated levels of behavior problems in children. The fact sheet uses data about more than 30,000 six to 11-year-olds from the 2003 National Survey of Children's Health. Data sources and definitions are provided. (Contains 4 figures.)