Surrey Police said the road was closed for several hours between the McLaren roundabout to the Otter roundabout while emergency services were in attendance and investigations were carried out.
Mike Flewitt, chief executive officer of McLaren Automotive, said:
Two McLaren employees were killed when the sports car they were travelling in crashed near to the Formula 1 giant's technology centre.
The staff members, who were in a blue Subaru Impreza, were pronounced dead at the scene following a collision with a Ford Transit van on the A320 in Ottershaw, Surrey, at 12.10pm today.
A man in his 60s who was driving the van was taken to St George's Hospital in Tooting with serious injuries, Surrey Police said.
McLaren confirmed that the two staff worked for McLaren Automotive which produces road cars and is based at the same site as the McLaren Formula 1 team.
A Surrey Police spokesman said: "Officers are appealing for witnesses. Anyone who may have seen the incident, or the events surrounding it, is urged to contact Surrey Police as a matter of urgency."
Lewis Hamilton will join Mercedes from next season on a three-year contract.
The decision to leave McLaren after a 14-year association with the team has been described by one source close to Hamilton as "the toughest of his career".
In a statement Hamilton said: "It is now time for me to take on a fresh challenge and I am very excited to begin a new chapter racing for the Mercedes Formula One Team. Mercedes-Benz has such an incredible heritage in motorsport, along with a passion for winning, which I share."
He added: "Together, we can grow and rise to this new challenge. I believe that I can help steer the Silver Arrows to the top and achieve our joint ambitions of winning the world championships."
Mexican Sergio Perez will replace Lewis Hamilton at McLaren next season. McLaren said: "Sergio's new deal means that he will begin a driving partnership with 2009 world champion Jenson Button."
Lewis Hamilton will end his 14-year association with McLaren at the end of the season and switch to Mercedes.
The 27-year-old driver will reportedly sign a three-year deal worth £15 million a year.
According to reports today in several British newspapers, an announcement could come later on Friday.
Hamilton's contract negotiations have been a running saga all season.