Police said the crash happened in the Austin neighborhood's 900-block of North Central Avenue just before 4 a.m.
A 25-year-old woman was driving a Nissan SUV southbound on Central Avenue when she veered off the street and hit a tree, police said.
The driver and two passengers, a 2-year-old girl and a 4-year-old girl, were taken to Stroger Hospital in critical condition.
CPD's Major Accidents Unit is investigating.
Police did not immediately provide further information about the crash.