In a tweet Thursday, Toronto police said the incident occurred in the Queen Street West and Triller Avenue area at around 11:35 a.m.
Police said the man was working on a home when he fell from the roof.
Officers said he was taken to hospital “under trauma protocol.”
Police said the man is in his 70s or 80s.
According to police, the Ministry of Labour is investigating.
In a statement emailed to Global News, the Ministry of Labour, Immigration, Training and Skills Development said an inspector has been assigned and the investigation is ongoing.