The victim's name has not been released.
Firefighters found him inside the burning unit, unconscious on his bedroom floor. He was rushed to Good Samaritan Hospital, where he later died. An investigation was underway into what started the fire.
No one else was hurt. But the fire forced 145 residents of the complex to evacuate.
Lombard Fire Department Battalion Chief Chuck Ralis says firefighters also helped two residents in wheelchairs out of the 72-unit building.
Fire officials say damage to the building and its contents is estimated at $225,000.