In 1945, a United States Public Health Service team in Monrovia, Liberia, began the use of synthetic insecticides for indoor residual spraying (IRS) and as a larvicide, with the goal of controlling malaria in the Liberian capital. In the early 1950s, the project was “scaled up” to reach the surrounding areas, and in 1953, the World Health Organization (WHO) launched an antimalaria program in the upcountry region of Central Province, Liberia. It was initially based solely upon IRS, as it was one of a series of pilot projects whose goal was to determine the feasibility of malaria eradication in tropical Africa. The malaria control project in Monrovia constituted the first large-scale use of synthetic insecticide to combat malaria in tropical Africa, and the WHO pilot project in Central Province was one of a first cluster of projects initiated to explore the efficacy of IRS in a variety of African ecological zones. These projects encountered a spate of difficulties that foreshadowed the general retreat from malaria eradication efforts across tropical Africa by the mid-1960s.