As large-scale biobanks are developed for translational genomic research and health care quality improvement, they are also becoming attractive as sites for public health interventions, such as population-based preventive sequencing for actionable variants. With the rapid advance of next-generation sequencing, the feasibility of such population health interventions is also increasing. The resulting confluence of public health norms, fiduciary clinical obligations, and ethical expectations for research creates a number of challenges. This chapter on public health genomics examines three examples of projects facing such challenges, in order to anticipate the ethical and policy issues that public health uses of research biobanks raise for those responsible for their design and governance. The chapter looks at issues of informed consent, return of results, and community engagement.