Alexander Khalilov, 22, faces three counts of second-degree murder after police were called to an Etobicoke residence around 6:50 p.m. on Monday and found the bodies.
Tatiana Khalilova, 49, also of Toronto, was the accused's mother. Also pronounced dead at the scene were Svetlana Babaega, 76, and Victor Zybin, 76, both from Russia.
Police said there were obvious signs of injury on the bodies, which were discovered by a fourth family member at a townhouse complex in the Burnhamthorpe Road and Dundas Street West area.
Police tracked the suspect, who was armed with a knife, to a nearby ravine. A brief standoff ended peacefully, and Khalilov was arrested and charged.
He appeared in court Tuesday.
The post-mortem examinations have not yet been completed.