This dissertation contrasts Hong Kong’s and the International Settlement’s management of malaria and of leprosy from the 1880s through the 1940s. This dissertation has two main objectives. Firstly it examines the historical management of malaria and leprosy within specific geo-political contexts. By focusing on British possessions in coastal China, this project explores the production of colonial medical knowledge within a transnational context, presents new and original analyses of the local history of the disease, and bridges the historiography of the British Empire and that of modern China. Secondly this dissertation contrasts Hong Kong’s and the International Settlement’s management of each of these two diseases. By focusing specifically on these two British possessions in coastal China, this project provides insights into the Imperial conceptualisation and management of Chinese bodies and Chinese environments, sheds light on broader historiographical debates regarding the role of colonial medicine, and complicates modern debates about the nature of colonialism in China.