Wurz signed a deal with WilliamsF1 to become the team's official test and reserve driver at the beginning of 2006. He drove the third car at all Friday sessions in . It was announced on 3 August 2006 that Wurz would replace Mark Webber as a race driver at Williams for the season. This was Wurz's first full-time race drive since 2000, and his teammate was Nico Rosberg. At the Monaco GP on 27 May 2007, Wurz scored his first points for Williams, finishing in 7th place after qualifying 11th. He came third for the third time in his F1 career at the Canadian Grand Prix on 10 June 2007, having started 19th on the grid in an action packed race. He nearly repeated this at the European Grand Prix, but was unable to overtake Mark Webber at the final chicane. That race turned out to be Wurz's last points finish. On 8 October 2007 he announced his immediate retirement from Formula One, meaning that the 2007 Chinese Grand Prix was his final race. He cited doubts over his own commitment as the main reason for his departure. He was replaced by Williams test driver Kazuki Nakajima for the final race of the 2007 season in Brazil.