The purposes of this study were to investigate blood profiles and nutrient intakes of groups that are different in obese levels, and to find the credible predictor of insulin resistance. The subjects were classified as normal weight (%IBW${leq}$ 110), obese without MS and obese with MS according to IDF definition of the risk group in metabolic syndrome (MS). Subjects of this study were included 137 (59 boys, 78 girls) free living children and adolescents (mean age $12.6{pm}3.4$ years) in Gangneung area, South Korea. %IBW of normal weight (94.9%), obese without MS (123.8%) and obese with MS (131.5%) were significantly different among groups. HOMA-IR had positive correlations with TG (r = 0.634), waist circumference (r = 0.553), atherogenic index (r = 0.513), %IBW (r = 0.453) and ALT (r = 0.360), but showed negative correlations with HDL cholesterol (r = -0.417, p < 0.001). HOMA-IR showed positive correlation with polyunsaturated fatty acid intake (p < 0.05). The energy intake of obese with MS was 1762 kcal/day which was not significantly different from those of normal weight and obese without MS. Total fatty acid intakes of two obese groups were significantly higher than that of normal weight. The results of this study suggest that waist circumference and ALT as well as TG, atherogenic index and weight can be credible indices to predict the insulin resistance in children and in adolescents. In addition, nutrition education and adequate diet should be provided to prevent MS in children and in adolescents.