Chicago firefighters were at the building near the intersection of North Milwaukee Avenue and West Raven Street around 1 a.m.
A woman was found in the doorway of the building with burns on over 30 percent of her body. Inside the building, firefighters found a man's body. He has been identified at 63-year-old Timothy Coughlin of the 6300-block of West Raven Street.
The cause of the fire is under investigation.