State corrections officials say inmates from Calipatria State Prison were working on the side of the road when the accident happened Friday.
Details of the crash were not released.
The name of the man killed was withheld pending notification of family.
The injured inmate was identified as 45-year-old Richard Warrick. He was transported to a hospital for treatment of moderate injuries and has returned to the prison.
Warrick is serving a 3-year sentence for possession of a controlled substance, burglary, and receiving stolen property.