|In the 1930's, a massive cholera prevention movement was carried out by the three Shanghai public health authorities (belonging to the International Settlement, the French Concession, and the Shanghai city government). The movement was part of the collaboration between the League of Nations Health Organization (LNHO) and the Nationalist government of the Republic of China, and the main goal was mass inoculation. This article examines the steps that made the movement possible and the way they were carried out. It also explores the political ties between the three authorities and the characteristics of public health administration, especially in the International Settlement and within the Shanghai city government. From the late 1920's, the political relations between the three health authorities were in a delicate state. However, Ludwick Rajchman, the LNHO delegate, encouraged each authority, and finally they agreed to cooperate in the prevention movement. Even so, the International Settlement and the city government differed over how to prevent cholera. The attitudes of each authority in carrying out the movement reflected such differences and differences in the legal systems of the three districts.