OBJECTIVE. Our goal was to identify characteristics associated with inadequate sleep for a national random sample of elementary school-aged children (6 -11 years) and adolescents (12-17 years).METHODS. Data from 68 418 participants in the 2003 National Survey of Children's Health were analyzed by using weighted bivariate and multivariate regression models. The dependent variable was report of not getting enough sleep for a child of his or her age Ն1 night of the past week. Independent variables included demographic characteristics, child health, school and other activities, and family life.RESULTS. Parents of elementary school-aged children with inadequate sleep were more likely to report that their child was having problems at school or had a father with fair or poor health. Parents of adolescents with inadequate sleep were more likely to report that their child had an atopic condition, frequent or severe headaches, a parent with less-than-excellent emotional health, or experienced frequent parental anger. Inadequate sleep in both age groups was associated with parental report that their child usually or always displayed depressive symptomatology, family disagreements involved heated arguing, or parental concern that the child was not always safe at home, at school, or in their neighborhood.CONCLUSIONS. Approximately 15 million American children are affected by inadequate sleep. Primary care providers should routinely identify and address inadequate sleep and its associated health, school, and family factors.www.pediatrics.org/cgi