The prevalence of the metabolic syndrome is highest among Hispanic adults. However, studies exploring the metabolic syndrome in overweight Hispanic youth are lacking. Subjects were 126 overweight children (8-13 yr of age) with a family history for type 2 diabetes. The metabolic syndrome was defined as having at least three of the following: abdominal obesity, low high-density lipoprotein (HDL) cholesterol, hypertriglyceridemia, hypertension, and/or impaired glucose tolerance. Insulin sensitivity was determined by the frequently sampled iv glucose tolerance test and minimal modeling. The prevalence of abdominal obesity, low HDL cholesterol, hypertriglyceridemia, systolic and diastolic hypertension, and impaired glucose tolerance was 62, 67, 26, 22, 4, and 27%, respectively. The presence of zero, one, two, or three or more features of the metabolic syndrome was 9, 22, 38, and 30%, respectively. After controlling for body composition, insulin sensitivity was positively related to HDL cholesterol (P < 0.01) and negatively related to triglycerides (P < 0.001) and systolic (P < 0.01) and diastolic blood pressure (P < 0.05). Insulin sensitivity significantly decreased (P < 0.001) as the number of features of the metabolic syndrome increased. In conclusion, overweight Hispanic youth with a family history for type 2 diabetes are at increased risk for cardiovascular disease and type 2 diabetes, and this appears to be due to decreased insulin sensitivity. Improving insulin resistance may be crucial for the prevention of chronic disease in this at-risk population.