OBJECTIVE: The purpose of this study was to develop percentage of fat and waist circumference cut-points in prepubertal children with the intention of defining obesity associated with cardiovascular disease (CVD) risk. RESEARCH METHODS AND PROCEDURES: A cross-sectional analysis of 87 prepubertal children aged 4 to 11 years was used. Percentage of body fat was determined by DXA. Waist circumference was measured to the nearest millimeter. Receiver Operating Characteristic analyses of percentage of fat and waist circumference were used to develop cut-points for individuals with adverse levels of CVD risk factors. RESULTS: The risk factors selected for analyses (i.e., fasting insulin, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, and total cholesterol/high-density lipoprotein cholesterol) were significantly related to percentage of body fat and waist circumference. Likelihood ratios were used to identify percentage of fat and waist circumference cut-points associated with adverse cardiovascular risk profiles. Two cut-points, an upper cut-point of 33% body fat and a lower cut-point of 20% body fat, were derived. Waist circumference cut-points indicative of adverse and normal risk-factor profiles were 71 cm and 61 cm, respectively. DISCUSSION: The data indicate that children with > or =33% body fat and children with a waist circumference > or =71 cm were more likely to possess an adverse CVD risk-factor profile than a normal risk-factor profile. The likelihood of children with < 20% body fat or a waist circumference < 61 cm possessing an adverse CVD risk-factor profile as opposed to a normal risk-factor profile was small. The cut-points describe an adequate health-related definition of childhood obesity.