Manuel Pellegrini has left West Ham with immediate effect, the club have announced on Saturday evening.
The Hammers slipped to their fourth straight home defeat against Leicester on Saturday evening and lie one point above the relegation zone.
A West Ham statement read: “Joint-Chairmen David Sullivan and David Gold, along with the board and everyone at West Ham United, would like to place on record their thanks to Manuel for his service over the past 18 months.”
Sullivan said: “It is with great disappointment that we’ve had to make this decision. Manuel is a gentleman and it has been a real pleasure to work with someone of his calibre.
“However, it has become clear that a change is required to get the club back on track in line with our ambitions this season.
“We felt it was necessary to act now in order to give the new manager as much time as possible to try and achieve that goal.”