This dissertation examines the relationship between race and bodily health in the British West Indies and the Carolina/Georgia Lowcountry from the late seventeenth through the early nineteenth century. In the eighteenth century, planters often justified African slavery by claiming that Africans, unlike Europeans, had bodies particularly suited to labor in warm climates. Historians have tended to take these claims as evidence of a growing sense of biological race in plantation societies. Much of this work, though, relies on published sources. This dissertation examines these public sources, including medical manuals, natural histories, and political pamphlets, alongside private sources, particularly the personal correspondence of planters and slaveholders to uncover a different story of race and slavery. These two source types reveal significant discrepancies between planters’ public rhetoric and private beliefs about health, race, and the environment in plantation societies. First, correspondence between the Greater Caribbean and Britain demonstrates that health and disease did not contribute to the development of racial slavery in the Atlantic. Second, these sources show how and why planters manipulated public conceptions of climate and health to justify and maintain a system of racial slavery. Planters insisted on climate-based arguments for slavery in spite of their experiences in the Americas, rather than because of them. Slaveholders contributed to the construction of a biological concept of race by making arguments about health differences between Africans and Europeans that they neither experienced nor believed. Nevertheless, their arguments entered the public record and consciousness, and the resultant development of racial thinking had profound consequences that continue to the present day. This dissertation demonstrates the critical importance of the environment to the history of race.