The blaze broke out at the home on 66th Street in Glendale just before 12:30 a.m. Tuesday.
The three boys, ages 9, 11 and 16, were forced to jump from the second-story window.
They were put on stretchers and neck braces and taken to Elmhurst Hospital. They boys are expected to survive.
In addition, two adults were also hospitalized with non-life threatening injuries.
The cause of the fire, which started in the rear of the second floor, is under investigation.
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