There is little consensus on the best obesity index associated with metabolic risk factors among the population with normal both body mass index (BMI) and waist circumference (WC). We therefore evaluated the association between anthropometric indices and metabolic risk factors in a Korean population with normal BMI and WC. This cross-sectional study involved 2,952 participants aged 20-79 years who had normal BMI and WC, based on the Fourth Korea National Health and Nutrition Examination Surveys conducted in 2008. The receiver operating characteristic (ROC) curves were generated to identify the optimal measurement of obesity for the prediction of metabolic risk factors in this population. The area under the ROC curve value for waist-to-height ratio (WHtR) in prediction of metabolic syndrome (MetS) and its components was higher than that for BMI and WC. Among individuals with normal BMI and WC, prevalence of all metabolic risk factors and MetS significantly increased across the quartiles of WHtR in both men and women. After adjustment for potential confounders, the Odds Ratios (95% confidence intervals) for MetS in the second, third, and fourth quartiles of WHtR compared to the first quartile of WHtR were 3.53 (2.12-5.89), 6.06 (3.52-10.43), and 7.11 (4.08-12.38) in men, and 1.66 (1.01-2.72), 2.79 (1.81-4.30), and 2.82 (1.76-4.52) in women, respectively. In conclusion, WHtR has the best predictive value for evaluating the metabolic risk factors compared to BMI or WC alone among subjects with normal BMI and WC.