The cause of death has not been ascertained yet.
Media reports said that the man, in his fifties, whose name has not been revealed, was a long-term resident of Cong Hoa Street in Tan Binh District.
He had not been seen leaving his room for several days, the reports said.
On Monday morning, neighbors reported a stench covering the complex in which the Canadian man had rented a small room.
When the landlord got no response after banging on the man’s door, he immediately contacted the local police.
The police broke into the room and found the foreigner’s decaying body.
According to neighbors, the man had rented the room for two years and lived alone.
Ho Chi Minh City, Vietnam's largest metropolis, is one of the most visited destinations in the country, with four million foreigners arriving in the first seven months of 2018.