Technical Abstract: Hyperinsulinemia/insulin resistance is a risk factor for future type 2 diabetes. Fasting insulin and blood lipids serve as direct indicators of subsequent risk and as biochemical markers of metabolically significant adiposity. We examined the feasibility of obtaining fasting blood samples and report correlates of these biochemical markers in an understudied population sample. Fasting samples were requested from African-American girls, 8.00 to 10.99 years of age, for insulin, glucose, and lipid concentrations. Indices of insulin sensitivity and secretion were calculated and correlated with anthropometric, dietary, physical activity, and body composition data. Samples were obtained from 119 of 210 (57%) girls, varying from 5% to 86% across the four field centers. Glucose ranged from 71 to 104 mg/dL. Eleven percent had insulin concentrations >20 mU/liter. One girl had a triglyceride concentration >130 mg/dL. Thirteen percent had total cholesterol >200 mg/dL, whereas all subjects had high-density lipoprotein (HDL)-cholesterol of > or =35 mg/dL. Fourteen percent had low-density lipoprotein levels >130 mg/dL. Insulin concentrations showed consistently strong associations with measures of body weight (rs = 0.54 to 0.67); glucose, HDL, and LDL showed weaker correlations (rs = -0.11 to 0.22). Insulin concentration was highly correlated with indices of both insulin secretion and resistance (rs = 0.99). Fasting blood samples in young African-American girls were obtained with reasonable cooperation in three of the four field centers involved in this community-based study. Fasting insulin, glucose, LDL, and HDL concentrations may help evaluate future diabetes and cardiovascular risk in children of this age.