Police say the stabbing occurred at a residence in downtown Toronto.
The victim suffered serious injuries. The suspect fled.
The suspect, Elijah Roberts, 28, is considered armed and dangerous, police say.
Anyone who spots him is advised to call 911 and not to approach him.
Roberts is described as a 5'9" white male who weighs 177 pounds. He has dark-coloured hair, a beard, tattoos on both arms and recent bruising on his face.
Police say "he may be wearing a bandage on his head."
Anyone with information for investigators is asked to call police at 416-808-5200. Information can also be passed on anonymously through Crime Stoppers at 416-222-8477.