This paper argues that bioethics as a field should broaden its scope to include the ethics of war, focusing on war’s public health effects. The “Introduction” section describes the bioethics literature on war, which emphasizes clinical and research topics while omitting public health. The section, “War as a public health crisis” demonstrates the need for a public health ethics approach by framing war as a public health crisis. The section, “Bioethics principles for war and public health” proposes six bioethics principles (...) for war that address its public health dimensions: health justice, accountability, dignified lives, public health sustainability, nonmaleficence, and public health maximization. The section, “Justifying and applying bioethical principles” shows how these principles inform ethical analysis, including just war theory and military ethics. The section, “From principles to practice” envisions ways in which bioethicists can promote these principles in practice through research, teaching, and service. The “Conclusion” section urges bioethicists to engage with war as a public health crisis, including calling attention to war’s impact on civilians, especially women, children, and other vulnerable groups. (shrink)