Objectives : This study was to determine how the perception and the satisfaction of outpatients who utilized clinics and hospitals are structurally related with their willingness to utilize the same institution in the future. Methods : Three hundred and ten responses (via convenient sampling) were collected from 5 hospitals and 20 clinics located in Seoul listed in the "Korea National Hospital Directory 2005". Service quality was utilized as the satisfaction measurement tool. For analysis, we used a structural equation modeling method. Results : The determining factors for general satisfaction with medical services are as follows: medical staff, reasonability of payment, comfort and accessibility. Such results may involve increased competition in the medical market and increased demands for quality medical services, which drive the patients to visit hospitals on their own on the basis of changed determining factors for satisfaction. Conclusions : The structural equation model showed that the satisfaction of outpatients with the quality of medical services is influenced by a few sub-dimensional satisfaction factors. Among these sub-dimensional satisfaction factors, the satisfaction with medical staff and payment were determined to exert a significant effect on overall satisfaction with the quality of medical services. The structural relationship in which overall satisfaction perceived by patients significantly influences their willingness to use the same institution in the future was also verified.