Aim: To characterize trends and clustering of cardiometabolic risk factors in 12-17-year-old non-Hispanic white, non-Hispanic black (NHB), Mexican-American (MA), and multiracial American (MRA) adolescents. Methods: Data from the 1999-2000 to 2007-2008 U. S. National Health and Nutrition Examination Surveys were used for this investigation. Clustering of cardiometabolic risk factors was determined using cardiometabolic risk factor clustering score (cMetS) computed by aggregating z scores of mean arterial blood pressure, triglycerides, fasting blood glucose, waist circumference, and high-density lipoprotein cholesterol. Results: There were significant increases in waist circumference and high-density lipoprotein cholesterol, and decreases in low density lipoprotein cholesterol, triglycerides, and mean arterial blood pressure in the 10-year period between 1999-2000 and 2007-2008. There were gender and racial/ethnic differences in cMetS, with NHB having a more favorable cMetS for each studied time point. Overall, cMetS decreased by 93% in the 10-year period between 1999-2000 and 2007-2008. cMetS decreased by 98% and 77.3% for male and female adolescents, respectively, in the period between 1999-2000 and 2007-2008. With the exception of Mexican-American and multiracial American female adolescents, all racial/ethnic groups had improved cMetS values on comparing mean cMetS values of 1999-2000 with mean values of 2007-2008. Compared with other racial/ethnic groups, NHB male and female adolescents had the most improved cMetS. Conclusion: Because clustering of cardiometabolic risk factors is predictive of adult health status, early lifestyle intervention in adolescence may help slow down the progress and delay or prevent the onset of cardiovascular diseases in adulthood. (C) 2012 Society for Adolescent Health and Medicine. All rights reserved.