Thirty-nine-year-old Grönholm said the decision was difficult, but he believed the time was right as he wanted to retire while still at the top level of the sport. This season he has already won five rallies to open a 10-point lead in the drivers' championship with five rounds remaining, and help the Blue Oval build a 46-point lead in the manufacturers' standings.
Grönholm arrived late in the WRC. After winning the Finnish championship four times, he made the breakthrough into the WRC in 1999. A year later he lifted the drivers' title on his first attempt at the full championship and claimed a second crown in 2002. He joined BP-Ford in 2006 and after a dream start with victory on his first two events in Monte Carlo and Sweden, he claimed a personal best seven wins to help Ford claim its first manufacturers' title since 1979. Victory in August's Rally Finland meant Grönholm became the first driver to win a full WRC event on seven occasions.
Rautiainen, 42, first co-drove for Grönholm in 1990. He spent several years out of the sport but the pair joined forces again in 1995 and have since enjoyed the longest-running partnership in the WRC.
"This has been an incredibly hard decision for me to make," said Grönholm. "Rallying has been my life for so many years and when the Monte Carlo Rally comes round in January to start next year's championship, it will feel strange not to be there. But the time is right for me to finish now. I wanted to stop while I still had the speed to win rallies. I didn't want to leave the decision too late so that I wasn't capable of winning any longer.
"This will allow me to spend more time with my wife and three children. They have fully supported me all the way through my career and I would like to thank them for that. I could not have achieved what I have without their encouragement. Now this decision is made, I want to concentrate on the remaining five rounds of the season. We lead both the drivers' and manufacturers' championships and I would like nothing more than to end my career with another title," he said.
Ford of Europe President and CEO John Fleming acknowledged Grönholm's contribution to Ford's recent WRC successes. "Marcus has done a superb job for the team and it is no coincidence that his arrival in 2006, coupled with the introduction of the new Focus RS World Rally Car, signalled the start of one of our most successful periods in the WRC. We greatly appreciate his contribution during the last two seasons and will miss him and the inspiration he brings to the team," he said.
Ford Team RS director Jost Capito added: "I will be sorry to see Marcus go but he will leave behind some great memories at Ford. He played an influential part in our first world title for 27 years last season and his appetite for victory is undiminished this year. He is one of only two drivers to have won 30 rallies in the WRC and he will go into the history books as one of the sport's all-time greats. On behalf of the whole team, I would like to thank Marcus and Timo for their whole-hearted commitment during the past two seasons and wish them the best of luck for the future."
BP-Ford team director Malcolm Wilson paid tribute to Grönholm. "I'm sorry that he is going to stop but I fully respect his decision. His driving achievements speak for themselves but his input to the team, in particular his encouragement and help to Mikko Hirvonen, will be greatly missed as they have formed the strongest driving partnership in the WRC. We knew his retirement was a possibility. We are developing plans for next season and when they are finalised we will confirm them. In the meantime I would like to try to help Marcus and Timo to achieve a unique feat by ending their careers with a world title in their final season together," said Wilson.