The RAC rescue helicopter was called to a crash near Pinjarra on Sunday evening.
The accident happened just before 7pm and involved a single vehicle crashing into a paddock off Pinjarra Road.
Police and ambulance crews were called.
At this stage, the extent of injuries to the two occupants of the vehicle is unknown.
One was airlifted to Royal Perth Hospital, the other was taken by ambulance to Peel Health Campus.
Investigations are under way.