Background: The purpose of this study is to assume appropriate outpatient consultation time for each clinical department on the basis of measured outpatient consultation time and satisfaction of outpatient. Methods: We surveyed the feeling and satisfactory outpatient consultation time, satisfaction, revisiting intention and recommendation to others to 1,105 patients of single general hospital in Gyeonggi-do and measured their real outpatient consultation time from October 28 to November 25 in 2013. On the basis of satisfaction, we estimated appropriate outpatient consultation time through area under the receiver operating characteristic curve in logistic regression model. Results: Feeling outpatient consultation time was 5.1 minutess, satisfactory outpatient consultation time which was suggested by patient was 6.3 minutes, and real outpatient consultation time was 4.2 minutes. Department which had longest real outpatient consultation time was infection (7 minutes) and department which had longest satisfactory outpatient consultation time was neurology (9.4 minutes). From the univariate and the multiple linear regression analysis, real outpatient consultation time was longer in pulmonology patient, new patient and afternoon patient, satisfactory outpatient consultation time was longer in infection, neurology, neuropsychiatry, neurosurgery, and rehabilitation patient. Appropriate real outpatient consultation time was suggested as 5.6 minutes which differentiated high and low satisfied patient group. However, we could not assume appropriate OCT for each clinical department because the number of patient who had bad satisfaction was too low. Conclusion: To improve patient`s satisfaction, we hope outpatient reservation system is operated as each patient`s outpatient consultation time is at least 5.6 minutes.