A mix of economic interests, humanitarianism, and political concerns over future regional security and stability drove twentieth century attempts to counter indigenous morbidity and depopulation in the Pacific. However, chronic under-resourcing impeded colonial health developments. An opportunity for change came in 1913, when the International Health Board of the Rockefeller Foundation negotiated with the British Colonial Office for joint programmes to control hookworm disease in Britain's tropical dependencies. After surveying the health situation and potential for work in the Pacific region in 1916, a short-lived campaign followed in Fiji (1917-1918). The American philanthropy then focused on Australia, where co-operative hookworm programmes advanced the objectives of the Foundation and increased Federal involvement in public health while and also served the interests of "White Australia". Under Dr. Sylvester Lambert, work in the Island Pacific resumed in 1920, to promote the health and economic viability ofindigenous labour in the Australian territories of Papua and New Guinea. Plantation interests supported survey and treatment work in the British Solomon Island Protectorate, and in 1922 the Fiji campaign re-opened. Lambert expanded the International Health Board's involvement from initial hookworm survey and treatment programmes in the British and New Zealand dependencies in the South Pacific, into other aspects of public health and medical services: water supplies and latrines; a bacteriological laboratory in Suva; hospital expansion; and medical education. Integrating local initiatives, Lambert advocated a Unified Pacific Medical Service, in which key elements were centralisation., rationalisation and affordability. The most radical aspect of his plan was the development of a Central Medical School for the Pacific territories, to provide targeted professional training for indigenous medical practitioners who had a crucial (although still subservient) role in economic service delivery and the diffusion of biomedical understanding among local communities. Also controversial - and Jess successful - were attempts to improve the career opportunities and standard of European Medical Officers, by creating a single medical service for the British Pacific dependencies. Attempts to achieve these goals influenced the shape and outcome of health and medical services which developed in the different island communities by 1939, when Lambert's retirement signalled an end to active Rockefeller Foundation involvement. This thesis examrnes the ways in which colonial administrations, medical staff, the Rockefeller Foundation, labour and mission interests, and Pacific Islanders interacted in the introduction of the dramatically new medical concepts and practices of western science (and specifically tropical medicine) and their effect on indigenous populations.