Firefighters were called to the 300 block of Buxmont Street at 8:00 a.m.
The fire was reported to be in the basement of the home.
The 70-year-old man who died was living in the basement, investigators said. There were no working smoke detectors.
The fire department has not released the man's name, but said he is the brother of a retired Philadelphia Police officer.
The fire was brought under control shortly before 8:30 a.m.
The fire marshal's office is investigating.