Victor Schœlcher is best known for having issued the decree that definitively abolished slavery in the French Empire in 1848. However, the racial theories at the core of Schœlcher’s political thought have yet to be studied thoroughly. This paper explores how he used the natural history of man in support of abolitionism, at a time when an emerging “racial science” was informing most political discourse. Drawing on his published writings as well as his personal archives in the Schœlcher Library (Fort-de-France) and the Natural History Museum (Paris), the aim is to explain how a republican like himself leaned on a malleable and temporalized concept of human nature to promote political projects that sought to “regenerate” inferiorized races for egalitarian purposes. The paper looks at Schœlcher's readings and references, his Atlantic travels (to the United-States, Mexico, the colonial Caribbean, Haiti, Senegal, and Egypt), and his affiliations to various transnational abolitionist and learned societies (such as the "Société Ethnologique de Paris") in order to argue that the epistemology of natural history shaped his political project and approach to liberty, equality and fraternity. Articulating his abolitionist discourse around the ideas of racial regeneration, civilization, and progress also led Schœlcher to support the independence of the “old colonies” while backing the “new colonization” of Africa. He was indeed a fervent advocate of projects like the creation of Liberia and Sierra Leone, where former American slaves were to form free societies and help "civilize" the rest of the African continent.