The Old Trafford side are 14th in the table after nine games. They have won only one of their last eight games in all competitions.
"Erik ten Hag has left his role as Manchester United men's first-team manager," the club said in a statement.
"Ruud van Nistelrooy will take charge of the team as interim head coach, supported by the current coaching team, whilst a permanent head coach is recruited."
The 54-year-old Dutchman's hold on his job looked precarious for most of last season as United recorded their worst Premier League finish, in eighth place, while British billionaire and INEOS chairman Jim Ratcliffe taking charge of football operations.
Ruud van Nistelrooy, left, alongside Erik ten Hag this month. (AP PHOTO)
A surprise FA Cup final win over Manchester City, however, plus the fact Ten Hag was able to blame numerous injuries for their poor form earned him another chance.
Ten Hag was appointed in April 2022. Before the start of this season he signed a new contract to extend his stay until 2026 and was given another chance to restore the 20-times English league champions to former glories.
Early results this season, however, suggested Ten Hag was not going to achieve that.
With agencies
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