The prevalence of obesity is increasing among all age and racial groups in the United States. There is, however, a disproportionate rise in the prevalence of obesity among African-Americans and Hispanic/Mexican Americans. Obesity is a major contributor to the insulin resistant syndrome (IRS), a condition of multiple metabolic abnormalities that is a precursor to type 2 diabetes, and confers a high risk for cardiovascular events. The estimated prevalence of IRS is also greater in Mexican Americans and African-Americans than in Caucasians. The IRS is identifiable in children, and as with adults, there are racial differences in its expression even at a young age. The obesity-associated diseases, including diabetes and hypertension, are found at higher rates within the minority races compared with Caucasians. However, there are differences, in that obesity-related hypertension occurs at higher rates among African-Americans, and obesity-related diabetes occurs at higher rates among Mexican Americans. Race/ethnic differences in lifestyle behaviors and economic disadvantage may account for some of the race disparity in obesity-related diseases and disease outcomes. Environmental factors, however, do not explain all of the race disparity in disease expression, indicating that there are genetic/molecular factors that are operational as well.