The appearance and spread of severe acute respiratory syndrome (SARS) on a global level raised vital legal and ethical issues. National and international responses to SARS have profound implications for 3 important ethical values: privacy, liberty, and the duty to protect the public's health. This article examines, through legal and ethical lenses, various methods that countries used in reaction to the SARS outbreak: surveillance and contact tracing, isolation and quarantine, and travel restrictions. These responses, at least in some combination, succeeded in bringing the outbreak to an end. The article articulates a set of legal and ethical recommendations for responding to infectious disease threats, seeking to reconcile the tension between the public's health and individual rights to privacy, liberty, and freedom of movement. The ethical values that inform the recommendations include the precautionary principle, the least restrictive/intrusive alternative, justice, and transparency. Development of a set of legal and ethical recommendations becomes even more essential when, as was true with SARS and will undoubtedly be the case with future epidemics, scientific uncertainty is pervasive and urgent public health action is required.