The number of U.S. children living in poverty increased in 2007--continuing an upward trend dating back to 2000: in 2007, 13.3 million children were living in poverty, up from 11.6 million children in 2000. The percentage of children living in families with incomes below the poverty line has increased from 16.2 percent in 2000 to 18.0 percent in 2007: nearly one child in five are poor. Child poverty merits attention because a substantial body of research links poverty with lower levels of child well-being. For a variety of reasons, when compared with children from more affluent families, poor children are more likely to have low academic achievement, to drop out of school, and to have health, behavioral, and emotional problems. These linkages are particularly strong for children whose families experience deep poverty, who are poor during early childhood, and who are trapped in poverty for a long time. This Research Brief draws on Census data for 2007 to present a statistical portrait of children in poverty in the United States, updating similar briefs Child Trends produced in 1999 and 2002. The brief highlights research on the consequences of poverty for children and suggests program and policy approaches that hold promise for decreasing poverty among low-income children and their families. (Contains 109 notes and 2 figures.)