The mother of the boy, identified by family as Nathaniel Dixon, was in critical condition after the 3:30 a.m. fire in the 1800-block of Arbor Lane. The fire occurred in an apartment on the third floor.
When firefighters arrived they could not see the fire from outside the building, but police officers inside found unit with a hot door handle. Upon entering the apartment, they found an unconscious woman and toddler.
Both victims were taken in critical condition to Presence Saint Joseph Medical Center in Joliet, where the boy was pronounced dead.
The mother was flown to an intensive burn care unit with severe burns.
The cause of the fire is under investigation.