Officers were called to the scene on the A303 between Podimore and Ilchester in Somerset at 21:30 BST on Monday.
Avon and Somerset Police said a black Isuzu Rodeo pick-up collided with a red Mazda 6 car which had broken down.
The man in the pick up was pronounced dead at the scene. He has not been formally identified, but his next of kin have been made aware, police said.
The occupants of the Mazda were treated by ambulance crews at the roadside.
The road was closed in both directions overnight until about 09:00 BST so that an investigation could take place.