The stabbing occurred at around 2:45 p.m. Thursday near the intersection of Sherbourne and Wellesley streets, Toronto EMS says.
One of the two is a male, though the gender of the second victim is not immediately known.
The gender of the person who died is also not immediately clear, said Toronto police. The surviving victim, meanwhile, is in critical condition.
It's not clear if police are searching for a suspect.
A stretch of Sherbourne Street around Earl Street has been closed as police investigate.
The 75 Sherbourne bus is diverting northbound through Wellesley, Parliament and Howard streets as police investigate.
The bus is diverting southbound through Isabella, Jarvis and Wellesley streets.Suggest a correction