Police said the crash happened in the Streeterville neighborhood's 400-block of East Illinois Street just after 1:15 p.m.
A 65-year-old woman and a 5-year-old child were trying to cross the intersection when a Gray Toyota minivan struck them, police said.
Police said the woman, who suffered head and neck injuries, was taken to Northwestern Hospital in serious condition. The child, who suffered lower body injuries, was transported in good condition to Lurie Children's Hospital, where they were treated and released.
The driver, a 53-year-old man, did not suffer any injuries, but was transported to Northwestern Hospital for observation, where he was treated and released, police said. He was issued a citation.
CPD's Major Auto Accident detectives are investigating.
Further information was not immediately available.