For most children who come to the attention of child welfare services and are the subject of an investigation, the majority of those investigations result in closed cases, with children remaining at home, receiving no other child welfare system (CWS) services. Whether or not the investigation results in an open case, children in contact with the CWS are likely to have substantial developmental disadvantages and more attention to the opportunities for providing or coordinating services will appear warranted. Minimal interventions that many receive will be insufficient to wipeout the long-term risks they probably will face. Additionally, risk assessment analyses found that child welfare agencies were very concerned about substance abuse and serious mental health problems among family members. What influences case workers’ decisions significantly about whether to leave children in the home or remove them is poor parenting and related issues of motivation to change and cooperation with the CWS. In order to provide a clearer understanding of the life outcomes for children and families that come into contact with the CWS, the Administration on Children, Youth and Families of the U.S. Department of Health and Human Services conducted the National Survey of Child and Adolescent Well-Being (NSCAW). NSCAW examines the characteristics, needs, experiences, and outcomes for these children and families, as well as information about crucial program, policy, and practice issues of concern to the Federal Government, State and local governments, and child welfare agencies. The NSCAW cohort includes 6,231 children, age birth to 15 who had contact with the CWS within a 15-month period that began in October 1999. This report presents the findings from this first national look at the characteristics of children and families who come into contact with the CWS. Tables, references, and appendixes A-B