Emergency services are at the scene of a "potentially serious collision" on the A38 at Notter, Saltash.
Police have reported that the incident involved a car and a lorry.
A Devon and Cornwall Police spokesperson said: "One woman is believed to be seriously injured. Next of kin are being sought.
"The public are being advised to avoid the area while officers work at the scene."
Due to the collision, School Road, Landrake, and Eastbound at Stoketon Cross both have road closures in place.
Updates as we have them.