Glenn Roeder has had his contract terminated with immediate effect by West Ham.
Trevor Brooking, who filled in when Roeder underwent surgery last season on a brain tumour, will take over as caretaker boss.
Roeder returned to work at Upton Park in the summer following the club's relegation from the Premiership.
West Ham started the season with a win at Preston but defeat on Saturday at
Rotherham has been followed by him receiving the sack.
A statement on the Hammers' official website said: "West Ham United wish to announce that Glenn Roeder's contract has been terminated with immediate effect and he has been relieved of his duties as team manager.
"The board would like to place on record their gratitude to Glenn for his hard work and commitment to the club since his permanent appointment in June 2001.
"This was demonstrated by his desire to return to active duty so quickly after his recent illness and I am sure all supporters recognise how dedicated he was to the club.
"The board however feel that following relegation to the First Division, the club's best chance of returning to the Premiership at the first attempt would be enhanced by a change of manager."
"Trevor Brooking CBE will once again act as caretaker manager until such time as a permanent successor is appointed.
"Interviews will begin immediately and Glenn's successor will be appointed in
"Until that time the board has complete confidence in Trevor's ability to
manage the team starting at home on Tuesday night against Bradford City."
Roeder himself issued a brief statement on the Hammers' website.
"I found the decision of the board of West Ham United to terminate my contract after only four matches disappointing," he said.
"However, I would like to put on record my thanks to the players, staff, and
fans of West Ham United, a truly great club, and wish them every success for the