This article studies diplomatic history in its physical dimensions. Its point of departure is the interpretation of the term ‘corps diplomatique’ in a literal sense. The article introduces the concept of the diplomatic body as a diplomat's body and as a body with diplomatic functions and meanings. Based on material relating to the British Legation in Kabul from 1922 until 1947, the body's ubiquity in international relations is revealed through the themes of space, language, and medicine. The article first looks at the impact of Kabul's spatial conditions and the physical reactions it excited in British diplomats. It then considers the bodies of Afghanistan's ruling elite as objects of British attention, whose appearance was documented in diplomatic records. Descriptions of these bodies in diplomatic language expressed intimacy and consensus as well as estrangement in British–Afghan relations. In addition to the metaphorical use of the diplomatic body, the provision of healthcare through the Legation's medical unit addressed the needs of British and Afghan bodies alike. It was also employed to further diplomatic ends by extending colonial medicine to the Afghan population. The study of the Legation's physical practices ultimately reveals the diplomatic mission's colonial origins and character.