We consider the public health applications of genomic technologies as viewed through the lens of the public health code of ethics. We note, for example, the potential for genomics to increase our appreciation for the public health value of interdependence, the potential for some genomic tools to exacerbate health disparities because of their inaccessibility by the poor and the way in which genomics forces public health to refine its notions of prevention. The public health code of ethics sheds light on concerns raised by commercial genomic products that are not discussed in detail by more clinically oriented perspectives. In addition, the concerns raised by genomics highlight areas of our understanding of the ethical principles of public health in which further refinement may be necessary.