This study was performed to explore the effect of customer satisfaction and switching barriers on customer royalties in medical services. 900 households, 1% sample were randomly selected from K city located in Kangwon province. Interview survey was performed with structured questionnaire for the entire people, 923 persons who experienced medical service utilization during one year before survey on time, september, 2002. In comparison of switching barriers by sociodemographic characteristics, lower income group and lower educated group showed the higher level of recognition level on availability of changing the service provider significantly. In terms of economic loss as one of switching barriers, the group of over aged 61, the lower income group and the lower educated group felt higher than other groups. Also, the time loss of switching barrier was recognized in 41-60 aged group and employee in service industry highly. For the perceived risk factor as another switching barrier, the high educated group showed the higher recognition level in performance risk and felt higher social risk than other groups. In analysis of customer satisfaction and loyalty levels by switching barrier components, the lower level of availability of changing the service provider and the higher level of recognition for economic and time loss, they showed the higher satisfaction and loyalty levels. In final step, multiple regression analysis showed the positive relationship between customer satisfaction, switching barrier and customer loyalties. Besides, the moderating effect of switching barrier in relationship between customer satisfaction and loyalties was significant and this results suggests that the influence of customer satisfaction to customer loyalties might be weakened in high level of recognition for switching barrier. In conclusion, perceived risk of economic and time loss as switching barrier is an important factor and should be considered in planning of marketing strategy carefully in terms of defensive marketing.