Two cars collided next to the Bicester Village Park and Ride carpark.
A BMW and a Renault van crashed at the roundabout junction with the A41 and Vendee Drive at around 8:15pm yesterday.
Sadly, a 77-year-old man, and an 80-year-old woman, died at the scene. Their next of kin have been informed.
The driver and passenger in the BMW sustained minor injuries and have been discharged from hospital.
Investigating officer Sergeant Phil Hanham of the Serious Collision Investigation Unit, said: "This was a very serious incident which has sadly resulted in the death of two people.
"We would like to speak to anyone who either witnessed the collision or saw the vehicles before this incident.
"We would also like any drivers or cyclists in the area at the time with dash-cam footage to check if these vehicles are present to assist with the investigation.
Please contact Thames Valley Police on 101 quoting reference 43190177431 or make a report online."