Manuel Pellegrini has been sacked by West Ham with the club hovering just above the Premier League relegation zone.
A 2-1 defeat at home to high-flying Leicester City on Saturday proved to be the final straw.
West Ham are just a point above the bottom three and co-chairman David Sullivan said the board had to act.
Pellegrini arrived at the London Stadium in May 2018 on a three-year deal and led the club to a top-10 finish in his maiden campaign.
However, the Chilean who guided Manchester City to Premier League glory in the 2013-14 campaign has seen West Ham lose 10 of their 19 top-flight matches this term despite forking out big sums on the likes of Sebastien Haller and Pablo Fornals in the close season.
Former boss David Moyes is the early bookmakers’ favourite to replace Pellegrini, while Bournemouth manager Eddie Howe and Rafael Benitez have previously been linked with the role.