A 33-year-old West Pymble man was killed when the car he was a passenger in rolled on Forest Road on Saturday night.
The man was thrown from the vehicle and found deceased at the scene.
A 35-year-old Ermington man was airlifted to St George Hospital in a serious condition.
The pair were in a Mitsubishi Challenger, which had been travelling east on Forest Road.
According to police the vehicle had left the road and rolled a number of times.
A crime scene was established and traffic diversions were put in place with assistance from the Shoalhaven City Council for about seven hours.
Crime scene officers and officers from the Southern Region Crash Investigation Unit conducted investigations at the scene.
Police investigations into the cause of the accident are continuing.