The family of Anthony Cox, from Batley, say he was rushed to Leeds General Infirmary with stab wounds to his chest and side at around 3.30am.
The stabbing took place at Club TBC on Bradford Road.
A West Yorkshire Police spokesperson said: "At 3.48am today (10/11) police were called to an incident at TBC nightclub, in Bradford Road, Batley.
"A 34-year-old man had been assaulted with a broken glass during a fight in the outside smoking area.
"He was found to have received serious injuries to his chest. He is currently in hospital receiving treatment. His injuries are not considered life threatening.
"Detectives are continuing enquiries into the incident today.
"Anyone who witnessed the incident or who has any information that could assist the investigation is asked to contact Kirklees District CID via 101 quoting crime reference 13180564228 or call the independent charity Crimestoppers anonymously on 0800 555 111."
Club TBC have been approached for comment.