Fear-based public health campaigns have been the subject of an intense moral and empirical debate. We examined how New York City, under Mayor Michael Bloomberg, used fear-based appeals to confront three challenges to public health: high rates of tobacco use, obesity, and HIV infection. New York City’s use of this type of messaging may have set a precedent. Other state and local health departments will have to navigate how and whether to use fear in a context where it is possible to assert that it can serve the interests of public health. But this will not reduce the need to carefully balance efficacy, uncertainty, stigma, marginalization, emotional burdens, justice, community participation, and scientific credibility.