“The Genome and The Biome: Cystic Fibrosis @ Six Feet Apart” is a history and ethnography of the cystic fibrosis community, focused predominantly on the United States. It takes the relatively common genetic disease, cystic fibrosis, as a case study of novel diagnostic technologies, risk, and sociality, providing new insights into the lived experience of genetic disease. Using historical and ethnographic methods, I trace how a bacterial epidemic in the CF patient population irrevocably altered the CF community as policymakers made efforts to mitigate infectious risk. With increasingly austere guidelines recommending the separation of people with CF from one another, the CF community was reconfigured by infectious risk, migrating from CF camps and shared hospital wards to the early internet of list servers and chatrooms, to the contemporary space of social media. As CF community shifted shape, the demographics of CF also evolved from a pediatric disease that was lethal in childhood to a disease of both kids and adults. I argue that amidst a rapidly evolving prognosis, CF sociality came to inform what I call prognostic imaginaries, the visualized projections that an individual can see, hope, or fear for their lives. Though CF summer camps normalized the day-to-day experience of CF, they could erode individuals’ taken for grant sense of a normative lifespan or restore individuals’ imaginations of adulthood, with college graduation, career, marriage, and longevity modeled by CF camp elders. If CF camps played a key role in informing prognostic imagination, the CF internet enables an important kind of horizoning work. While prognostic imagination speaks to what individuals can see, hope, fear or plan for the future, horizoning work forges workable knowledge to guide action when projections are insufficient, weaving hopes and fears into tenuous plans and hard decisions regarding life with CF. With a sustained and intimate focus on the embodied and temporal experience of CF, I illustrate how CF lives complicate normative conceptions of time and future and deepen our understanding of the risky microbial world.