Flames exploded out of the top floor window of a home in the 100-block of North Waller Street shortly after 4:45 p.m.
The building is believed to be a multi-unit residential building. Chicago fire officials said they first received a call about a fire at a home next door, but when firefighter arrived the fire was out.
Minutes later, a person in the home next door called in about the blaze that firefighters are still battling.
CFD said no injuries have yet been reported. It was not immediately known what caused the fire or how many people were in the building at the time it broke up.
The most intense flames appear to be on the top floor of the house.
No further details were immediately available.