The first started at about 2:30 p.m. in the 500-block of Park Avenue and firefighters responded within a minute from a fire house down the street.
Flames were coming from the basement, where firefighters encountered a lot of clutter, said James Eggert, fire chief for the River Forest Fire Department.
The fire was put out in about 15 minutes, Eggert said. The man's body was found in the basement.
The Cook County Medical Examiner's Office confirmed the death, but did not immediately have other information.