Singh and colleagues provide the latest estimates of and changes in obesity and overweight prevalence among US adolescents aged 10 to 17 years using 2 large, nationally representative samples from 2003 and 2007. Overall, in 2007, 16.4% of US children were obese and 31.6% were overweight. The obesity prevalence in 2007 varied from a low of 9.6% for children in Oregon to a high of 21.9% for those in Mississippi. Overweight prevalence varied from a low of 23.1% for children in Utah to a high of 44.5% for children in Mississippi. Among boys, the observed obesity prevalence in 2007 was lowest in Oregon (11.0%) and highest in Arkansas (27.2%), while girls in Wyoming and Texas had the lowest and highest obesity prevalences (5.5% and 20.2%), respectively. All of the states in 2007 fell considerably short of the Healthy People 2010 goal of a child obesity prevalence of 5%. Prevention programs for reducing childhood obesity must include social policy measures aimed at improving the broader social and physical environments that create obesogenic conditions that put children at risk of poor diet, physical inactivity, and sedentary activities.