Objective: Metabolically Healthy Obese (MHO) is the obese phenotype which may exist in the absence of metabolic abnormalities. However, data is insufficient about MHO in South Korea. Furthermore, there is still debate regarding the implications of the MHO. If MHO do exist, total medical cost of the subjects with MHO should not be higher than nonobese without metabolic syndrome. The aim of this study is to compare the medical cost of MHO with nonobese. Methods: The whole date of this study are from National Health Insurance Service-National Sample Cohort of South Korea. The definition of MHO which we used is from Meigs JB et al. We sorted out the subjects with MHO by health check-up data, and eliminated who is not eligible by ICD codes and added together total cost. Results: The subjects with MHO had cosumed more medical resources than nonobese without metabolic syndrome. In general, total medical cost increased in direct proportion to the numbers of risk factors which the subjects had regardless of obese. However, total medical cost of the obese subjects was highrt than the nonobese subjects if they had the same numbers of metabolic components. Conclusion: Our results denied the vary exist of MHO in South Korea. We concluded that the more important key is the number of risk factors which the subjects have, than obese itself. Futhermore, obesity might have the major role among the metabolic components.