목적: Obstructive sleep apnea (OSA) is well known as potential risk factor for various chronic disease in adult, such as type 2 diabetes, hypertension and cardiovascular disease. The aim of this study is to investigate the association between OSA and metabolic syndrome (MS) in Korean adult. 방법:This study included 127 Korean men who were referred to Department of Otorhinlaryngology-Head and Neck Surgery, Korea University Ansan Hospital. Subjects have underwent the overnight polysomnography and than divided into control group (AHI less than 5) and OSA group (AHI more than 5) by AHI. In addition, several measurement and blood tests have been performed to identify the components for MS. MS was defined according to the Adult Treatment Panel (ATP) III criteria 1) Waist circumference (WC) > 90 cm for males, 2) Blood pressure (BP) > 130/85 mmHg 3) Fasting Blood Glucose (FBS) > 100 mg/dl 4) high density lipoprotein (HDL) < 40 mg/dl for males, 5) Triglycerides (TG) > 150 mg/dl. We have analysis the presence of MS as OSA and the relationship between component of MS and OSA severity. 결과:Among 127 participants, 105 subjects were diagnosed as OSA (AHI > 5). The mean age and smoker percentage showed difference between OSA and control group (p=0.035, p=0.036, respectively). The prevalence of MS was significantly higher in OSA group (53.3%) compare to control group (18.2%) (p = 0.005). Prevalence of MS also increases depend on the severity of OSA. Odd ratio of MS in moderate OSA group is 6.947 (95% CI = 1.573, 30.676), and severe OSA group is 5.92 (95% CI = 1.692, 20.931), when compared with control group. 결론:The prevalence of MS is influenced by the severity of OSA in adult. We suggest that adult with OSA should have regular evaluation for the components of MS to identify the presence of MS.