Paramedics say a woman in her 30s has been pronounced dead in the city's northwest end.
Officers and paramedics were called for a stabbing Sunday morning at a building on King St, near Weston and Lawrence.
The woman was found without vital signs and pronounced dead on scene.
Police have taken a man into custody.
Homicide detectives have been called in to investigate the incident.
Officers have been searching dumpsters next to the building for evidence.