In the post-WWII decolonization era, the prospect of an open, decolonized Greenland, with unrestricted mobility for inhabitants, intensified medical experts’ pre-existing concerns over sexually transmitted diseases. During the colonial phase, medical and administrative authorities could govern Greenlanders as subjects and accordingly control their mobility and interactions with Europeans. However, the decolonization agenda threatened to undermine this situation. Greenland could no longer remain a colony, enclosed and sealed off from the rest of world by trade monopoly and strict limitations on access to the country imposed by the Danish authorities. Doctors were concerned by two impending shifts that threatened to undermine efforts to control sexually transmitted diseases. First, Greenland’s decolonized status would entail more or less free access to the country. Second, after decolonization, Greenlanders would have the status as citizens, and authorities could no longer govern them as (colonial) subjects. This paper demonstrates how medical authorities struggled with the Greenlanders’ transition from controllable (sexual) subjects to rights-bearing (sexual) citizens. The paper provides a fresh perspective concerning this watershed moment, between colonialism and the process of decolonization in Greenland.