This study examines the psychological effects of quarantine on individuals in Toronto, Canada, during the SARS outbreak. A web-based survey was conducted among 129 quarantined individuals, revealing a high prevalence of psychological distress, with 28.9% exhibiting symptoms of posttraumatic stress disorder (PTSD) and 31.2% showing signs of depression. Longer durations of quarantine and exposure to someone with SARS were associated with increased PTSD symptoms. The study highlights the need for better understanding and support for quarantined individuals to mitigate the adverse psychological impacts of quarantine.This study examines the psychological effects of quarantine on individuals in Toronto, Canada, during the SARS outbreak. A web-based survey was conducted among 129 quarantined individuals, revealing a high prevalence of psychological distress, with 28.9% exhibiting symptoms of posttraumatic stress disorder (PTSD) and 31.2% showing signs of depression. Longer durations of quarantine and exposure to someone with SARS were associated with increased PTSD symptoms. The study highlights the need for better understanding and support for quarantined individuals to mitigate the adverse psychological impacts of quarantine.