The biggest change in the current medical service market is the shift from producer-based approach to customer-based approach. Thus, there is a high necessity for an introduction of market-oriented and customer-oriented marketing activities in medical institutions. Especially, revisitation and positive word-of-mouth of customers are the most effective marketing methods of consistently obtaining customers and drawing new loyal customers. Hence, the factors influencing the reuse of medical services and word-of-mouth are demonstrated using SERVQUAL, and the results show that the service factors influencing reuse intentions on medical services are assurance, responsiveness, and tangibles and the factors strengthening word-of-mouth are empathy and assurance on the services provided by medical institutions. This study has determined that revistation and word-of-mouth of customers are not only influenced by satisfaction on medical services but by the quality itself as well. Therefore, medical service providers need to pursue standardized strategies in order to enhance the quality of medical services simultaneously in addition to simply increasing the customer satisfaction level.