Queensland detectives are investigating a suspicious death in custody after an assault at the state's Capricornia Correctional Centre.
A 31-year-old was assaulted at the prison on Saturday and died as a result of his injuries at Rockhampton Hospital on Sunday.
The death is considered a death in custody and homicide detectives are investigating.
Queensland Corrective Services confirmed the death in a statement on Sunday.
The victim was found by prison guards on Saturday morning.
"CPR commenced immediately, an ambulance was called and the man was transported to hospital where he passed away this afternoon," the statement said.
The statement said corrections was working with police and support was being provided to guards.
"Our condolences go to the man's family and friends," the statement said.
Corrections said it would be inappropriate to comment further.
It's the fourth death of an inmate at the prison this year, with The Courier Mail reporting in August three deaths over the course of the year.
Capricornia was the site of a mass riot in October last year which saw 45 prisoners face criminal charges.
An independent report into the prison released in April this year revealed factionalism among officers and inconsistent work practices.