The Missouri State Highway Patrol reports the accident happened just after 9:30, when 38-year-old Jeffrey Peoples was traveling two miles south of Cameron on U.S. Highway 69.
Troopers say he drove off the roadway, over-corrected, then lost control. The accident flipped his vehicle and he was ejected.
Peoples was flown to Truman Medical Center by helicopter, where he's being treated for serious injuries.
Troopers say he was not wearing a seat belt.