West Ham have sacked Manuel Pellegrini following their defeat to Leicester.
The Hammers' latest defeat on Saturday leaves them 17th, one point above the Premier League relegation zone.
Pellegrini departs after 18 months in charge, having been appointed in May 2018 on a three-year deal.
He led them to 10th last season but becomes the sixth Premier League manager to lose his job this campaign.
As well as their poor form in the league, West Ham were also knocked out of the Carabao Cup by League One side Oxford United, losing 4-0 in September.
West Ham won 24 of their 64 matches under the Chilean, losing 29.
Co-owner and chairman David 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 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."