The shooting occurred just before 12:30 a.m. at Cafe Cocomo, which is located at 650 Indiana St., police Sgt. Michael Andraychak said.
An unknown suspect shot the 23-year-old man inside the nightclub, and the victim was transported to a local hospital for treatment of his life-threatening injuries, Andraychak said.
As of 1:15 a.m., police were still at the scene of the crime investigating the shooting, he said.
No information on the suspect is available at this time.