Sunderland have sacked manager Gus Poyet after a run of just one victory in 12 Premier League games.
The Black Cats are one point above the relegation zone after Saturday's 4-0 home defeat by Aston Villa.
"Sadly, we have not made the progress that any of us had hoped for this season," said chairman Ellis Short.
"We find ourselves battling, once again, at the wrong end of the table. We have therefore made the difficult decision that a change is needed."
A Sunderland statement also added that an announcement about Poyet's successor would be made "in due course".
The Wearsiders face a trip to West Ham on Saturday before a derby against Newcastle on 5 April.

Poyet, 47, took training on Monday morning and then met chief executive Margaret Byrne and other board members to learn his fate.
The Uruguayan took over from Paolo Di Canio as manager at the Stadium of Light in October 2013 with the club bottom of the Premier League.
The former Brighton manager guided them to four victories and a draw from their final six league games to keep them up last season - a run that included wins at Chelsea and Manchester United and a draw at Manchester City.
Poyet also led the Wearsiders to the 2014 Capital One Cup final, which they lost to City.
"I would like to thank Gus for his endeavours during his time at the club, in particular last season's 'great escape' and cup final appearance, which will live long in the memory of every Sunderland fan," said Short.

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