My dissertation, Blood of the Nation, explores the role of blood in the formation of bionational identity in Cold War South Korea. It hypothesizes that blood functioned as a crucial bridge for reconfiguring the Korean nation from a community imagined through anticolonial cultural symbolism to a bionational body defined through the biological sciences. This project traces the convergence of scientific blood studies, medical blood treatments, and government blood regulations from the introduction of blood transfusion technologies during the Korean War (1950-1953) through the establishment of a national blood supply during the 1980s AIDS crisis. By examining the promulgation of a state-backed idea of "pure" Korean blood that regulated populations that threatened to "pollute" the normative national body, my study considers how colonial eugenics endured in the imperative to protect Korean blood and combined with developmental Cold War ambitions to optimize the nation. I concentrate particularly on the collusion of elite serologists and hematologists, public health policymakers, and clinical practitioners to police "impure" raced, gendered, and classed bloods to show how state programs such as mandatory pre-marital blood tests, pre-natal blood screenings, the pathologization of "mixed bloods," and biometric military examinations forwarded the authoritarian state's developmental goals. Meanwhile, I also examine how anomalous bodies have historically contested and negotiated the blood-based strictures on national inclusion. This dispute between blood regulators and those regulated by eugenicist policies raises important questions about nationalized public health in developing states through the South Korean case study. This study will propose that the Korean case reveals how postcolonial anxieties and Cold War imperatives coincided in bionationalist identity, and contribute to STS concerns about how modernization is achieved through transnational technoscientific means.