OBJECTIVES: The purpose of this study was to assess the cost-utility of bariatric surgery compared to non-surgical interventions in obese Korean people. METHODS: We used Markov model comparing the lifetime expected costs and quality adjusted life years (QALY) between bariatric surgery and non-surgery intervention from Korean Healthcare system perspectives. Our target cohort consisted of obese people defined as having a body mass index (BMI) of 30-40 in South Korea. The starting age of cohort was 30 years old. The non-surgical interventions include physician visit, exercise, diet, and pharmacotherapy. The cycle length was 1 year and used half-cycle correction. The health status comprised five states such as no comorbidity, mild/moderate comorbidity (diabetes or/and hypertension or/and, dyslipidemia), severe comorbidity (CHD or/and stroke), death due to CVD, and death due to other cause. Input data of transition probability for each disease status and utility weight calculated from the relationship between weight loss and QALY gain using Korean National Health and Nutrition Examination Survey data. The rate of death due to CVD and other cause were calculated Korean death statistics. The cost data was collected from the survey of 9 medical center who had conducted those obesity treatments and Korean national health insurance statistics, based on 2011 costs. Discount of 5% was applied in cost and QALY. Incremental cost-effectiveness ratio (ICER) of bariatric surgery compared to non-surgery interventions was calculated. RESULTS: The cost-utility study indicated that bariatric surgery had US$1,522 Incremental costs and 0.86 Incremental QALY compared non-surgical interventions. Through the base case analysis, ICER was US$1771/QALY. The sensitivity analyses under a variety of assumption, robustness of the study results were also demonstrated. CONCLUSIONS: The study indicated that bariatric surgery was cost-effective alternative to non-surgical interventions over lifetime, providing substantial lifetime benefits in obese Korean people.