Crews were on the scene in the 5900-block of South Elizabeth Street in Chicago's Englewood neighborhood just before 1 p.m.
CFD said the elderly person was taken to University of Chicago Medical Center.
Video of the scene appeared to show the fire took place in a home, and a large number of police officers and firefighters responded.
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It was not immediately clear how the fire began.
This is a developing story; check back with ABC7 Chicago for updates.