In 2009–2010, more than one-third of U.S. adults (35.7%) and almost 17% of children and adolescents were obese. There was no significant change in obesity prevalence among adults or children from 2007–2008 to 2009–2010. Obesity prevalence did not differ between men and women. Adults aged 60 and over were more likely to be obese than younger adults. Among women, obesity prevalence increased from 33.4% in 1999–2000 to 35.8% in 2009–2010, while no significant change was observed in men. For children and adolescents, obesity prevalence increased among boys (from 14.0% to 18.6%) but not among girls (from 13.8% to 15.0%). Overall, obesity prevalence remained stable in recent years, but there was a significant increase among men and boys over the last decade. The Healthy People 2010 goals of 15% obesity among adults and 5% among children were not met. Obesity is defined as a BMI of 30 or higher for adults and as a BMI at or above the 95th percentile for children. The National Health and Nutrition Examination Survey (NHANES) provided the data, which is a cross-sectional survey of the U.S. civilian noninstitutionalized population. The data were analyzed using complex survey methods, including age adjustment and statistical significance testing. The findings highlight the continued high prevalence of obesity in the U.S. and the need for ongoing monitoring and intervention.In 2009–2010, more than one-third of U.S. adults (35.7%) and almost 17% of children and adolescents were obese. There was no significant change in obesity prevalence among adults or children from 2007–2008 to 2009–2010. Obesity prevalence did not differ between men and women. Adults aged 60 and over were more likely to be obese than younger adults. Among women, obesity prevalence increased from 33.4% in 1999–2000 to 35.8% in 2009–2010, while no significant change was observed in men. For children and adolescents, obesity prevalence increased among boys (from 14.0% to 18.6%) but not among girls (from 13.8% to 15.0%). Overall, obesity prevalence remained stable in recent years, but there was a significant increase among men and boys over the last decade. The Healthy People 2010 goals of 15% obesity among adults and 5% among children were not met. Obesity is defined as a BMI of 30 or higher for adults and as a BMI at or above the 95th percentile for children. The National Health and Nutrition Examination Survey (NHANES) provided the data, which is a cross-sectional survey of the U.S. civilian noninstitutionalized population. The data were analyzed using complex survey methods, including age adjustment and statistical significance testing. The findings highlight the continued high prevalence of obesity in the U.S. and the need for ongoing monitoring and intervention.