How do white nationalists use genetic ancestry tests? This article provides a qualitative analysis of posts from Stormfront, a white nationalist message board, to understand how white nationalists use genetic ancestry tests to advance ideological claims about the threat of genetic admixture. Starting in 2004, members of this message board began discussing the promises and pitfalls of using genetic ancestry tests to prove their whiteness. Using Goffman’s framework of stigma and impression management, we explore how they manage undesirable test results and genetic stigma amongst themselves – when they take genetic tests and discover they are partially non-white. Finally, this article looks at how they simultaneously deploy exclusionary or inclusionary strategies that challenge past concepts of whiteness built on the one-drop rule. Pragmatic concerns often drive their strategic positioning when confronted with undesirable test results, as they are aware that too strict exclusionary policies may impede the group’s demographical survival.