Background: The effectiveness of treatment of asthma has been assessed by lung function test, airway responsiveness and symptoms. But, they rarely capture the emotional and social impairment. Recently, questionnaires that reflect the quality of life(QOL) in asthma patients were developed. In this study, we evaluated the impairment on quality of life in Korean adult asthmatic patients cross-sectionally by using the QOL questionnaires of Juniper EF. Methods : One hundred eighty nine adult patients with over 1 year history of asthma were enrolled. The patients were asked to choose the five most important daily activities among 40 daily activities which were important in Korea. The QOL questionnaire was composed of 32 items in 4 domains(activity, symptom, emotion and exposure to environmental stimuli) and the response option was scored on a 7-point scale. Results 45.5% of patients who participated in this study were men, and 48.3% had atopy. The disease severities of asthma evaluated by physician were mild intermittent(31%), mild persistent(35%), moderate persistent(21%) and severe persistent(12%). Among 40 items of general daily activities, 19 items were chosen by more than 20 patients. Among them, running, walking uphills, hurried movement were most impaired daily activities. The QOL of our asthma patients showed statistical difference on disease severity, control state and symptom status during the last 3 months. The QOL was not influenced by sex, age or atopy score. Occupational asthma showed the lowest score on QOL in all 4 domains. On grouping with medications, the group with oral steroid noted statistically lower scores of QOL in all domains. The QOL score of asthma was well correlated with average symptom attacks during the last 3 months. Conclusion : According to our study, rapid control of asthma and lowering of the disease severity are essential for improvement of QOL. A QOL questionnaire in Korea should be developed in Korea.