From the late eleventh century to the early twelfth century, diplomatic relationships were unstable in East Asia, and thus the importance of diplomacy was emphasized between countries. In this period, each country sought to strengthen its sovereign power and used diplomacy as a means to accomplish this objective. Of particular importance, the exchange of medical services and medical education became a means of diplomacy. In one incident, Koryŏ requested from Song medical aid for the treatment of the king's illness. As the resumption of diplomatic relations between Koryŏ and Song began, Song responded positively to the request for assistance. In addition to the relationship between Koryŏ and Song, medical services provided by Koryŏ served to establish early diplomatic negotiations with the Wanyanbu Jurchen. Koryŏ also requested physicians from Japan with the aim to establish relations with them, but were unsuccessful in this as Japan's worldview and diplomatic customs were very different from Koryŏ's. Such requests served to promote interstate diplomatic relationships as it allowed for not only the exchange of medical knowledge, but also for conveying diplomatic messages and negotiations. This paper, centered on Koryŏ, reviews the circumstances and events during this period in which the use of medical services was used a means for diplomacy.