Igor Shteyn, 67, and Naum Berdichevsky, 76, died of smoke inhalation. The two men, who were roommates, were asleep. A third roommate was downstairs during the fire.
It took firefighters about three hours to extinguish the blaze.
Two other residents received minor injuries during the evacuation of that part of the six-story building, which has 304 beds. Thirty people were displaced by smoke and water damage, but are now being housed in another part of the facility.
"This guy came in the room and told everyone to get out of there because smoke was everywhere," said Katherine Bankston, nursing home resident.
Many relatives rushed to the scene to make sure their loved ones make it out safely.
"My mother just went in. The alarm went off at 10:00. They tried to calm my grandmother down. That's about it," said Patrick Chi, relative of nursing home resident.
The cause of the fire is currently under investigation. Although smoking is not allowed in the building, Niles police say nothing is being ruled out.
"I was told there was no electrical outlets in that closet. That's why they're investigating on how that fire started," said Sgt. Tom Davis, Niles Police Department.
There were working smoke detectors in the hallway, but officials are looking at whether the room's smoke detector was working.
"I understand that there were smoke detectors. I was told that smoke detectors in the main hallways were working. The smoke detector in the room where the fire was that is being -- it's under investigation by the state fire marshal," said Sgt. Davis.
Since 2007 the Illinois Department Of Public Health, which regulates and monitors nursing homes in the state, has been to the nursing home five times. Two of those times were for annual inspections and the others were for incidents or complaints. None of the complaints resulted in a Type A violation, which is considered the most serious.