Objectives-This report presents the development, plan, and operation of the National Survey of Children's Health(NSCH), a module of the State and Local Area Integrated Telephone Survey, conducted by the Centers for Disease Control and Prevention's(CDC) National Center for Health Statistics. This survey was designed to produce national and State-specific prevalence estimates for a variety of physical, emotional, and behavioral health indicators and measures of children's experiences with the health care system. The survey also includes questions about the family (e.g., parents' health status, stress and coping behaviors, family activities) and about respondents' perceptions of the neighborhoods where their children live. Primary funding for this survey was provided by the Maternal and Child Health Bureau, Health Resources and Services Administration. Additional support was received from the CDC's National Center for Infectious Diseases, using funds provided by the National Vaccine Program Office. Methods-A random-digit-dial sample of households with children under 18 years of age was selected from each of the 50 States and the District of Columbia. One child was randomly selected from all children in each identified household to be the subject of the survey. The respondent was the parent or guardian who knew the most about the child's health and health care. Results-A total of 102,353 interviews were completed from January 2003 to July 2004. The weighted overall response rate was 55.3%. A data file has been released that contains demographic information on the selected child, substantive health and well-being data for the child and his/her family, and sampling weights. Estimates based on the sampling weights generalize to the noninstitutionalized population of children in each State and nationwide.