Police the shooting happened in the Pullman neighborhood's 900-block of East 104th Street around 12:40 p.m.
The child, a 2-year-old boy, suffered a gunshot wound to the head. He was transported in critical condition to Comer Children's Hospital, where he was pronounced dead, police said.
Officers took a 31-year-old man into custody.
Area Two detectives are investigating. Police did not immediately provide further information.
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