This paper documents the role of malaria in the di ffusion of African slavery in the United States. The novel empirical evidence reveals that the introduction of malaria triggered a demand for malaria-resistant labor, which led to a massive expansion of African enslaved workers in the more malaria-infested areas. Further results document that, among African slaves, more malaria-resistant individuals, i.e. those born in the most malaria-ridden regions of Africa, commanded signi significantly higher prices.