Police say the attack happened at 2:30 a.m. on the lower level of the Sin on 7 Nightclub, located at 2220 Highway 7 at Keele Street.
Police say the man was beaten by three other men and suffered a slash wound to his neck. He was rushed to Sunnybook hospital. His injuries are not life-threatening.
Police have three men in custody. There is no word yet about charges.