The shooting happened just after midnight Saturday at Rudy's Lounge on the city's south side, the Chicago Tribune reported.
Police said the shots were fired into the bar from outside and stuck five people, killing one of them. The injured were transported to hospitals in stable condition.
"I just heard like four shots, and we all went down to the floor," said a 25-year-old man who declined to give his name.
It was unclear how many shooters there were, police said. No suspects have been arrested.