To assess the level of family stress that a child experiences, several questions from the National Survey of America's Families (NSAF) were combined to create a family stress index. The NSAF is a survey of more than 44,000 households representative of the United States as a whole and of 13 states, conducted as part of the Assessing the New Federalism project. The family stress index assigns one point for each of six stressful circumstances related to the inability to meet household expenses (including shelter and food), access to health care, and poor health. Children in families scoring two or higher on the index were categorized as living in stressful family environments. Findings indicate that half of children living in families with income below the federal poverty level also lived in stressful family environments. Thirty-five percent of children in families with incomes between 100 and 150% of the federal poverty level lived in stressful family environments. In contrast, just 1 child in 20 of those families with incomes over 3 times the federal poverty limit lived in stressful family environments. Levels of stress also vary by parents' education and by family structure. Children living in single-parent families or cohabiting families were more than twice as likely as those living in married couple families to live in stressful family environments. There are striking differences across the states in the proportion of children living in stressful family environments, ranging from a low of 15% in Wisconsin to a high of 30% in California. Overall, just over one in five children in the United States lives in a stressful family environment. Data suggest that children living in stressful family environments are nearly twice as likely to exhibit low levels of school engagement and are four times more likely to have high levels of behavioral and emotional problems. (Contains 1 table, 6 figures, and 16 references.) (SLD)