In recent years, precision medicine has emerged as a charismatic name for a growing movement to revolutionise biomedicine by bringing genomic knowledge and sequencing to clinical care. Increasingly, the precision revolution has also included a new paradigm called precision public health—part genomics, part informatics, part public health and part biomedicine. Advocates of precision public health, such as Sue Desmond-Hellmann, argue that adopting cutting-edge big data approaches will allow public health actors to precisely target populations who experience the highest burden of disease and mortality, creating more equitable health futures. In this article we analyse precision public health as a sociotechnical imaginary, examining how calls for precision shape which public health efforts are seen as necessary and desirable. By comparing the rhetoric of precision public health to precision warfare, we find that precision prescribes technical solutions to complex problems and promises data-driven futures free of uncertainty, unnecessary suffering and inefficient use of resources. We look at how these imagined futures shape the present as they animate public health initiatives in the Global South funded by powerful philanthropic organisations, such as the Bill & Melinda Gates Foundation, as well as local efforts to address cancer disparities in San Francisco. Through our analysis of the imaginary of precision public health, we identify an emerging tension between health equity goals and precision’s technical solutions. Using large datasets to target interventions with greater precision, we argue, fails to address the upstream social determinants of health that give rise to health disparities worldwide. Therefore, we urge caution around investing in precision without a complementary commitment to addressing the social and economic conditions that are the root cause of health inequality.