Objectives To assess the clinical value of ultrasonography (US) and bioelectrical impedance analysis (BIA) in analyzing abdominal fat contents of obese children and adolescents through comparison with MRI. A correlation with other obese related metabolic parameters was conducted. Methods Ninety 7-17-y-old obese children and adolescents (60 boys and 30 girls with mean age of 9.6 ± 2.9 y and mean BMI of 24.5 ± 4.5 kg/m2) were recruited. Metabolic parameters were measured, and insulin resistance was estimated according to homeostasis model assess-ment (HOMA-IR). On the same day abdomen subcutaneous fat thickness (SFTUS) was measured by US. Body fat mass (FMBIA) and abdominal visceral fat area (VFABIA) were analyzed by bioelectrical impedance analysis (BIA). After obtaining informed consent, abdominal MRI was performed in 20 subjects. Each section of umbilicus level was analyzed by image threshold value segmentation using SigmaScan Pro 5 and abdominal subcutaneous fat area (SFAMRI) and visceral fat area (VFAMRI) were calculated. Results (1) A strong positive association was found between SFTUS and SFAMRI (P< 0.05), VFABIA and VFAMRI (P < 0.01) respectively. (2) FMBIA and SFAMRI, VFAMRI, SFTUS also showed significant correlations (P < 0.05). (3) VFAMRI showed extremely significant positive correlations with TG, Insulin,C-peptide and HOMA-IR (P < 0.01 ) ; SFAMRI was also correlated positively with them (P < 0.05). (4) SFTUS was correlated positively with UA (uric acid), Insulin, 2HIns (insulin measured at 2 hours after meal), C-peptide,2HC-peptide (C-peptide measured at 2 hours after meal) and HOMA-IR (P < 0.01). (5) VFABIA was correlated significant positively with UA, insulin, TG, 2HIns and HOMA-IR. FMBIA showed positive correlation with UA, Insulin,2HIns, C-peptide, 2HC-peptide and HOMA-IR. Conclusions abdominal subcutaneous and visceral fat of obese children and adolescents evaluated by US and BIA are correlated well with those assessed by MRI, and also correlated well with TG, insulin, C-peptide and other metabolic biochemical parameters. Our data support the value of using cost effective, simple and convenient methods such as BIA and US to evaluate the obese and related metabolic risk of children and adolescents in clinical practice.