Officers are appealing for information following a road traffic collision in Cefn Fforest.
The collision occurred at approximately 3.35am on Sunday October 13 at on Bryn Road and involved a black Toyota Avensis and a male pedestrian.
The pedestrian has been taken to Prince Charles Hospital with life threatening injuries.
The road remained closed while collision investigators conducted enquiries.
Anyone who witnessed the collision is asked to call 101 quoting log 81 13/10/13.