OBJECTIVES: The purpose of this study is to assess health status of Korean adults with COPD using EQ5D and the association between health status and disease severity using spirometry as a lung function measure. METHODS: A stratified multistage clustered probability design was used to select a nationally representative sample. From the Fourth and Fifth Korea National Health and Nutrition Examination Survey, 20,261 adults over the age of 40 years were selected. These subjects completed the utility measure, EQ-5D-3L and were separated into four severity groups according to FEV1 percent of predicted normal using the GOLD clinical guideline. Population sampling weights were applied to adjust for the over-sampling of the minority groups. Regression analysis was conducted using EQ-5D as the dependent variable to estimate the association between COPD and EQ-5D index score with SAS Ver. 9.3 program. RESULTS: Among 20,261 adults, 2,087 COPD patients were selected based on GOLD criteria (a ratio of FEV1 to FVC of less than 0.7). The mean utility of COPD patients was 0.906(SE 0.004) compared to 0.922(SE 0.001) in the non-COPD control group. Utility was significantly reduced due to COPD(p=0.0001). Within each GOLD stage, the variation (SE) was wide [Stage I(n=858): 0.906(0.006); Stage II(n=1,091): 0.912(0.005); Stage III(n=119): 0.857(0.018); Stage IV(n=13): 0.780(0.071)]. EQ-5D was not significantly different by 4-stage disease severity but showed a trend of deterioration in Stage III and IV. In the post-hoc analysis, COPD patients were divided into two-stage groups [group 1: Stage I and II; group 2: Stage III and IV]. In this analysis, 2-stage severity had a negative association with utility(p=0.0009). CONCLUSIONS: The results demonstrate that COPD impaires utility and shows a relationship between utility and COPD disease severity in Korea.