A prisoner at the South Central Correctional Center at Licking was pronounced dead Thursday afternoon.
Authorities said Ferrell Thomas Cothern, 75, was pronounced dead at the institution.
Cothern was serving a 30-year sentence for first-degree assault, armed criminal action and first-degree burglary from Ozark County. He had been in prison since March 2009.
Officials said Cothern died of apparent natural causes.