An inmate housed at the South Central Correctional Center at Licking died Monday in a Springfield hospital.
Authorities said Orlan Helt, 62, died at 2:18 a.m. at Mercy Hospital in Springfield.
He was serving a 25-year sentence for second-degree robbery from Franklin County, three 15-year sentences for possession of a controlled substance and two counts of possession of chemical with intent to distribute and a seven-year sentence for unlawful use of drug paraphernalia, all from Washington County.
He had been held since June 2006.
An autopsy will be conducted.