The body of a 39-year-old man was found in his taxi which was parked in the layby of the A19 near Seaham.
The police were called to the scene shortly after 7am following concerns for the welfare of the man seen inside.
The unnamed man from Newcastle was found dead inside. According to the Sunderland Echo, his family have been informed.
A spokesperson for Durham Constabulary said:
"There are no suspicious circumstances surrounding his death."