West Bromwich Albion have parted company with manager Bryan Robson "by mutual consent".
Robson has left with West Brom ninth in the Championship
The former Middlesbrough manager took control of the club in November 2004 following Gary Megson's departure.
Club chairman Jeremy Peace said: "In view of the results since early 2006, it's been decided a change is necessary if the club is to achieve its aims."
Robson responded: "I've really enjoyed the short time I've been at Albion. The fans here have been different class."
Robson, 49, pulled off West Brom's dramatic escape from relegation in his first season at the Hawthorns on the final day of the 2004/05 Premiership season.
It's only a matter of time before they get it right, climb the table and win promotion
They were the first team in the history of the Premiership to stay up despite being bottom of the table on Boxing Day.
But Robson was unable to repeat the trick for a second year running and the Baggies were relegated along with Midlands rivals Birmingham and Sunderland.
Robson believes the players he leaves at the Hawthorns have the ability to bounce straight back this season.
"I do think there's a really good squad at the club," said Robson. "It's only a matter of time before they get it right, climb the table and win promotion.
"But as far as I'm concerned, the matter is now closed."
West Brom are currently ninth in the Championship having won three of their matches, lost two and drawn three this season.
Peace kept faith with Robson over the summer, insisting he wanted stability at the club and because Robson had twice won promotion to the Premiership when he was in charge at Middlesbrough.
However, after a disappointing start to the Championship campaign, Robson's tenure at the club was cut short after Saturday's 1-1 home draw with Southend.
Bryan spoke to the players and staff - they were subdued and disappointed
Caretaker manager Nigel Pearson
"This is a very important time for the club with promotion a priority and the best way forward is to make a change," Peace said.
First-team coach Nigel Pearson will assume control of selection affairs while the club considers its options. He will be at the helm for Tuesday's Carling Cup clash with Cheltenham.
Pearson, who has worked alongside Robson since the Middlesbrough era, said Robson's departure came as a real surprise.
"What has happened came as quite a big shock for all of us," said Pearson.
"He has a sense of unfinished business but that's football. Bryan spoke to the players at the training ground and also the staff. The players were subdued and disappointed.
"It has come out of the blue. I spoke to Bryan today and he is, as you would expect, disappointed and upset."
Robson had won just 19 of his 81 matches in charge of West Brom and only two league matches away from home.
The former Manchester United and England midfielder succeeded Megson at West Brom, after he was sacked in October 2004.
However, even then there was some opposition from supporters to his appointment despite serving the club with great distinction as a player.
His last job - at Bradford - culminated in the team's relegation to League One and his six years at Middlesbrough ended with Terry Venables being brought in.
Former West Brom striker Don Goodman, who played for the club between 1987-91, believes whoever takes over from Bryan Robson will inherit a good squad capable of promotion.
"Whoever comes in is going to be quite lucky as they will be able to work with a very good squad of players," Goodman told BBC Five Live.
"They should have the tools and firepower to fire West Brom up as players like that should really be in the top two.
"As to who it will be, that's difficult. Alan Curbishley is still out of job and if they get someone like him that would be a heck of a coup."