A 45-year-old Chippenham man died after being found at the wheel of a car on Loyalty Street.
Police attended just after 7am on Thursday to find the man slumped over the steering wheel of a Renault Scenic.
A Great Western Ambulance Service spokesman said it was called at 7.07am and told a man was unconscious behind the wheel.
Five minutes later a rapid response vehicle arrived on scene and was joined by an ambulance crew a minute later.
The man’s heart had stopped. He arrived at RUH at 7.57am and was declared dead just after 8am.
Police are not treating the man’s death as suspicious.