Steve Bruce has been sacked as manager of Sunderland.
The move comes following a poor run of results which have left the Black Cats 16th in the Premier League table.
"This has been a difficult time for everyone at Sunderland and is not a situation that any of us envisaged or expected to be in," chairman Ellis Shirt told the club's official website.
"It is my job as chairman to act in the best interests of our football club at all times and I can assure everyone that this is not a decision that I have taken lightly. Sadly results this season have simply not been good enough and I feel the time is right to make a change.
"I would like to personally place on record my thanks to him for his significant contribution to our football club over the past two and a half years and everyone here at Sunderland naturally wishes him the very best for the future."
Assistant manager Eric Black will take charge of the team until a replacement is found.
Former Aston Villa boss Martin O'Neill has been installed as the early favourite to succeed Bruce at the Stadium of Light.