The purpose of this study was to cull lessons from Toronto's experiences with large-scale quarantine during the outbreak of Severe Acute Respiratory Syndrome in early 2003. We focused on issues that affected the population's willingness to comply with quarantine. Information was acquired from interviews, telephone polling, and focus groups. Issues of quarantine legitimacy, criteria for quarantine, and the need to allow some quarantined healthcare workers to leave their homes to go to work were identified. Also important was the need to answer questions from people entering quarantine about the continuation of their wages, salaries, and other forms of income while they were not working, and about the means by which they would be supplied with groceries and other services necessary for daily living. The threat of enforcement had less effect on compliance than did the credibility of compliance-monitoring. Fighting boredom and other psychological stresses of quarantine, muting the forces of stigma against those in quarantine, and crafting and delivering effective and believable communications to a population of mixed cultures and languages also were critical. The need for officials to develop consistent quarantine policies, procedures, and public messages across jurisdictional boundaries was paramount.