The B4027 near Kidlington remains closed following a fatal crash earlier today.
At around 10.15am, a Vauxhall Vivaro van, a red VW Golf, a black Ford Mondeo and a grey Rover were involved in a collision on Bletchingdon Road, near Islip.
A man driving the Golf was pronounced dead at the scene.
The female passenger of the same car is in a serious but stable condition at Oxford's John Radcliffe Hospital.
The van driver, a man, is also in a serious condition and receiving treatment at hospital.
The B4027 is closed from the A34 southbound exit, signposted for Bletchingdon and Islip.
Accident investigators are working at the scene.
Witnesses to the collision are urged to contact Sgt Bryan Smith on 0845 8 505 505 or Crimestoppers on 0800 555 111.
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