Background & aims: Ultrasonographic measurements have been proposed to assess intra-abdominal adipose tissue. The aim of this study was to compare the relationship between waist circumference (WC), ultrasonographic measurements of intra-abdominal adipose tissue (UMA), and cardiovascular risk factors (CRF). Methods: We determined blood pressure (BP), fasting HDL-cholesterol, LDL-cholesterol, triglycerides, glucose, insulin resistance index HOMA, 2 h glucose in oral glucose tolerance test (oGTT), weight status (SDS-BMI), WC, and UMA in 89 obese children. Furthermore, we analyzed the changes of CRF, SDS-BMI, WC, and UMA in 29 obese children participating in a one-year lifestyle intervention. Results: in stepwise multivariable regression analysis, waist circumference was significantly associated to LDL-cholesterol, triglycerides, HOMA, and systolic blood pressure (adjusted variance (AV) 0.05-0.17). SDS-BMI was significantly related to triglycerides, HDL-cholesterol, 2 h glucose in oGTT and diastolic blood pressure (AV 0.12-0.15), while UMA was related significantly to HOMA (AV 0.04). The obese children participating in a lifestyle intervention significantly reduced their overweight, which was associated with a significant improvement of most CRF and a reduction of WC and UMA. Changes of WC were significantly correlated to changes of HDL-cholesterol (r = -0.45), HOMA (r = 0.37), glucose tolerance (r = 0.59), systolic BP (r = 0.60), and diastolic BP (r = 0.43), while change of SDS-BMI and UMA were not significantly related to any CRF. Conclusions: Compared to UMA, WC was stronger related to CRF in obese children. Therefore, the simple measurement of WC seems preferable as an indirect marker of CRF. (C) 2009 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.