For three of the injured, the condition is described as life-threatening.
Police have cordoned off the area where the shooting took place, at a restaurant complex in the River North area. According to reports, a release party for a new record was underway inside the nightclub.
Someone is said to have opened fire on the crowd on the sidewalk outside the club. The shots were fired from a vehicle that immediately drove away.
No suspect has been arrested for the deed that occurred late on Wednesday local time.