Sunnybrook Hospital says a COVID-19 outbreak has been declared in a surgical unit.
There are five confirmed cases of the virus.
"An initial 3 cases linked to each other were identified through our regular surveillance which triggered initial control measures and broader testing on the unit that identified two additional cases," the hospital said in a statement.
They say all are asymptomatic. Four are still in hospital and one was discharged.
Sunnybrook says the virus has not spread to other patient care areas of the hospital and it remains open for all scheduled clinics and procedures and emergency visits.