A prisoner has died in an apparent "medical event" at Townsville Men's Correctional Centre.
Queensland Corrective Services says the 48-year-old man suffered the event and collapsed on Thursday afternoon.
QCS officers tried to revive the man before paramedics arrived, but he died at the scene.
"Responding officers have been praised for their attempts to revive the man, and are being offered support from the management group," QCS said in a statement on Friday.
"Our condolences go to the man's family."
A report is being prepared for the coroner.